Security Bulletin: IBM QRadar SIEM contains multiple vulnerabilities

CVEID:   CVE-2024-46695
DESCRIPTION:   In the Linux kernel, the following vulnerability has been resolved: selinux,smack: don't bypass permissions check in inode_setsecctx hook Marek Gresko reports that the root user on an NFS client is able to change the security labels on files on an NFS filesystem that is exported with root squashing enabled. The end of the kerneldoc comment for __vfs_setxattr_noperm() states: * This function requires the caller to lock the inode's i_mutex before it * is executed. It also assumes that the
CWE:   CWE-276: Incorrect Default Permissions
CVSS Source:   IBM X-Force
CVSS Base score:   5.5
CVSS Vector:   (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)

CVEID:   CVE-2024-49949
DESCRIPTION:   In the Linux kernel, the following vulnerability has been resolved: net: avoid potential underflow in qdisc_pkt_len_init() with UFO After commit 7c6d2ecbda83 ("net: be more gentle about silly gso requests coming from user") virtio_net_hdr_to_skb() had sanity check to detect malicious attempts from user space to cook a bad GSO packet. Then commit cf9acc90c80ec ("net: virtio_net_hdr_to_skb: count transport header in UFO") while fixing one issue, allowed user space to cook a GSO packet with the following characteristic : IPv4 SKB_GSO_UDP, gso_size=3, skb->len = 28. When this packet arrives in qdisc_pkt_len_init(), we end up with hdr_len = 28 (IPv4 header + UDP header), matching skb->len Then the following sets gso_segs to 0 : gso_segs = DIV_ROUND_UP(skb->len - hdr_len, shinfo->gso_size); Then later we set qdisc_skb_cb(skb)->pkt_len to back to zero :/ qdisc_skb_cb(skb)->pkt_len += (gso_segs - 1) * hdr_len; This leads to the following crash in fq_codel [1] qdisc_pkt_len_init() is best effort, we only want an estimation of the bytes sent on the wire, not crashing the kernel. This patch is fixing this particular issue, a following one adds more sanity checks for another potential bug. [1] [ 70.724101] BUG: kernel NULL pointer dereference, address: 0000000000000000 [ 70.724561] #PF: supervisor read access in kernel mode [ 70.724561] #PF: error_code(0x0000) - not-present page [ 70.724561] PGD 10ac61067 P4D 10ac61067 PUD 107ee2067 PMD 0 [ 70.724561] Oops: Oops: 0000 [#1] SMP NOPTI [ 70.724561] CPU: 11 UID: 0 PID: 2163 Comm: b358537762 Not tainted 6.11.0-virtme #991 [ 70.724561] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 70.724561] RIP: 0010:fq_codel_enqueue (net/sched/sch_fq_codel.c:120 net/sched/sch_fq_codel.c:168 net/sched/sch_fq_codel.c:230) sch_fq_codel [ 70.724561] Code: 24 08 49 c1 e1 06 44 89 7c 24 18 45 31 ed 45 31 c0 31 ff 89 44 24 14 4c 03 8b 90 01 00 00 eb 04 39 ca 73 37 4d 8b 39 83 c7 01 <49> 8b 17 49 89 11 41 8b 57 28 45 8b 5f 34 49 c7 07 00 00 00 00 49 All code ======== 0: 24 08 and $0x8,%al 2: 49 c1 e1 06 shl $0x6,%r9 6: 44 89 7c 24 18 mov %r15d,0x18(%rsp) b: 45 31 ed xor %r13d,%r13d e: 45 31 c0 xor %r8d,%r8d 11: 31 ff xor %edi,%edi 13: 89 44 24 14 mov %eax,0x14(%rsp) 17: 4c 03 8b 90 01 00 00 add 0x190(%rbx),%r9 1e: eb 04 jmp 0x24 20: 39 ca cmp %ecx,%edx 22: 73 37 jae 0x5b 24: 4d 8b 39 mov (%r9),%r15 27: 83 c7 01 add $0x1,%edi 2a:* 49 8b 17 mov (%r15),%rdx <-- trapping instruction 2d: 49 89 11 mov %rdx,(%r9) 30: 41 8b 57 28 mov 0x28(%r15),%edx 34: 45 8b 5f 34 mov 0x34(%r15),%r11d 38: 49 c7 07 00 00 00 00 movq $0x0,(%r15) 3f: 49 rex.WB Code starting with the faulting instruction =========================================== 0: 49 8b 17 mov (%r15),%rdx 3: 49 89 11 mov %rdx,(%r9) 6: 41 8b 57 28 mov 0x28(%r15),%edx a: 45 8b 5f 34 mov 0x34(%r15),%r11d e: 49 c7 07 00 00 00 00 movq $0x0,(%r15) 15: 49 rex.WB [ 70.724561] RSP: 0018:ffff95ae85e6fb90 EFLAGS: 00000202 [ 70.724561] RAX: 0000000002000000 RBX: ffff95ae841de000 RCX: 0000000000000000 [ 70.724561] RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000001 [ 70.724561] RBP: ffff95ae85e6fbf8 R08: 0000000000000000 R09: ffff95b710a30000 [ 70.724561] R10: 0000000000000000 R11: bdf289445ce31881 R12: ffff95ae85e6fc58 [ 70.724561] R13: 0000000000000000 R14: 0000000000000040 R15: 0000000000000000 [ 70.724561] FS: 000000002c5c1380(0000) GS:ffff95bd7fcc0000(0000) knlGS:0000000000000000 [ 70.724561] CS: 0010 DS: 0000 ES: 0000 C ---truncated---
CWE:   CWE-476: NULL Pointer Dereference
CVSS Source:   NVD
CVSS Base score:   5.5
CVSS Vector:   (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)

CVEID:   CVE-2024-50082
DESCRIPTION:   In the Linux kernel, the following vulnerability has been resolved: blk-rq-qos: fix crash on rq_qos_wait vs. rq_qos_wake_function race We're seeing crashes from rq_qos_wake_function that look like this: BUG: unable to handle page fault for address: ffffafe180a40084 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 100000067 P4D 100000067 PUD 10027c067 PMD 10115d067 PTE 0 Oops: Oops: 0002 [#1] PREEMPT SMP PTI CPU: 17 UID: 0 PID: 0 Comm: swapper/17 Not tainted 6.12.0-rc3-00013-geca631b8fe80 #11 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014 RIP: 0010:_raw_spin_lock_irqsave+0x1d/0x40 Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 0f 1f 44 00 00 41 54 9c 41 5c fa 65 ff 05 62 97 30 4c 31 c0 ba 01 00 00 00 0f b1 17 75 0a 4c 89 e0 41 5c c3 cc cc cc cc 89 c6 e8 2c 0b 00 RSP: 0018:ffffafe180580ca0 EFLAGS: 00010046 RAX: 0000000000000000 RBX: ffffafe180a3f7a8 RCX: 0000000000000011 RDX: 0000000000000001 RSI: 0000000000000003 RDI: ffffafe180a40084 RBP: 0000000000000000 R08: 00000000001e7240 R09: 0000000000000011 R10: 0000000000000028 R11: 0000000000000888 R12: 0000000000000002 R13: ffffafe180a40084 R14: 0000000000000000 R15: 0000000000000003 FS: 0000000000000000(0000) GS:ffff9aaf1f280000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffafe180a40084 CR3: 000000010e428002 CR4: 0000000000770ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: try_to_wake_up+0x5a/0x6a0 rq_qos_wake_function+0x71/0x80 __wake_up_common+0x75/0xa0 __wake_up+0x36/0x60 scale_up.part.0+0x50/0x110 wb_timer_fn+0x227/0x450 ... So rq_qos_wake_function() calls wake_up_process(data->task), which calls try_to_wake_up(), which faults in raw_spin_lock_irqsave(&p->pi_lock). p comes from data->task, and data comes from the waitqueue entry, which is stored on the waiter's stack in rq_qos_wait(). Analyzing the core dump with drgn, I found that the waiter had already woken up and moved on to a completely unrelated code path, clobbering what was previously data->task. Meanwhile, the waker was passing the clobbered garbage in data->task to wake_up_process(), leading to the crash. What's happening is that in between rq_qos_wake_function() deleting the waitqueue entry and calling wake_up_process(), rq_qos_wait() is finding that it already got a token and returning. The race looks like this: rq_qos_wait() rq_qos_wake_function() ============================================================== prepare_to_wait_exclusive() data->got_token = true; list_del_init(&curr->entry); if (data.got_token) break; finish_wait(&rqw->wait, &data.wq); ^- returns immediately because list_empty_careful(&wq_entry->entry) is true ... return, go do something else ... wake_up_process(data->task) (NO LONGER VALID!)-^ Normally, finish_wait() is supposed to synchronize against the waker. But, as noted above, it is returning immediately because the waitqueue entry has already been removed from the waitqueue. The bug is that rq_qos_wake_function() is accessing the waitqueue entry AFTER deleting it. Note that autoremove_wake_function() wakes the waiter and THEN deletes the waitqueue entry, which is the proper order. Fix it by swapping the order. We also need to use list_del_init_careful() to match the list_empty_careful() in finish_wait().
CVSS Source:   NVD
CVSS Base score:   4.7
CVSS Vector:   (CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H)

CVEID:   CVE-2024-50099
DESCRIPTION:   In the Linux kernel, the following vulnerability has been resolved: arm64: probes: Remove broken LDR (literal) uprobe support The simulate_ldr_literal() and simulate_ldrsw_literal() functions are unsafe to use for uprobes. Both functions were originally written for use with kprobes, and access memory with plain C accesses. When uprobes was added, these were reused unmodified even though they cannot safely access user memory. There are three key problems: 1) The plain C accesses do not have corresponding extable entries, and thus if they encounter a fault the kernel will treat these as unintentional accesses to user memory, resulting in a BUG() which will kill the kernel thread, and likely lead to further issues (e.g. lockup or panic()). 2) The plain C accesses are subject to HW PAN and SW PAN, and so when either is in use, any attempt to simulate an access to user memory will fault. Thus neither simulate_ldr_literal() nor simulate_ldrsw_literal() can do anything useful when simulating a user instruction on any system with HW PAN or SW PAN. 3) The plain C accesses are privileged, as they run in kernel context, and in practice can access a small range of kernel virtual addresses. The instructions they simulate have a range of +/-1MiB, and since the simulated instructions must itself be a user instructions in the TTBR0 address range, these can address the final 1MiB of the TTBR1 acddress range by wrapping downwards from an address in the first 1MiB of the TTBR0 address range. In contemporary kernels the last 8MiB of TTBR1 address range is reserved, and accesses to this will always fault, meaning this is no worse than (1). Historically, it was theoretically possible for the linear map or vmemmap to spill into the final 8MiB of the TTBR1 address range, but in practice this is extremely unlikely to occur as this would require either: * Having enough physical memory to fill the entire linear map all the way to the final 1MiB of the TTBR1 address range. * Getting unlucky with KASLR randomization of the linear map such that the populated region happens to overlap with the last 1MiB of the TTBR address range. ... and in either case if we were to spill into the final page there would be larger problems as the final page would alias with error pointers. Practically speaking, (1) and (2) are the big issues. Given there have been no reports of problems since the broken code was introduced, it appears that no-one is relying on probing these instructions with uprobes. Avoid these issues by not allowing uprobes on LDR (literal) and LDRSW (literal), limiting the use of simulate_ldr_literal() and simulate_ldrsw_literal() to kprobes. Attempts to place uprobes on LDR (literal) and LDRSW (literal) will be rejected as arm_probe_decode_insn() will return INSN_REJECTED. In future we can consider introducing working uprobes support for these instructions, but this will require more significant work.
CVSS Source:   NVD
CVSS Base score:   5.5
CVSS Vector:   (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)

CVEID:   CVE-2024-50110
DESCRIPTION:   In the Linux kernel, the following vulnerability has been resolved: xfrm: fix one more kernel-infoleak in algo dumping During fuzz testing, the following issue was discovered: BUG: KMSAN: kernel-infoleak in _copy_to_iter+0x598/0x2a30 _copy_to_iter+0x598/0x2a30 __skb_datagram_iter+0x168/0x1060 skb_copy_datagram_iter+0x5b/0x220 netlink_recvmsg+0x362/0x1700 sock_recvmsg+0x2dc/0x390 __sys_recvfrom+0x381/0x6d0 __x64_sys_recvfrom+0x130/0x200 x64_sys_call+0x32c8/0x3cc0 do_syscall_64+0xd8/0x1c0 entry_SYSCALL_64_after_hwframe+0x79/0x81 Uninit was stored to memory at: copy_to_user_state_extra+0xcc1/0x1e00 dump_one_state+0x28c/0x5f0 xfrm_state_walk+0x548/0x11e0 xfrm_dump_sa+0x1e0/0x840 netlink_dump+0x943/0x1c40 __netlink_dump_start+0x746/0xdb0 xfrm_user_rcv_msg+0x429/0xc00 netlink_rcv_skb+0x613/0x780 xfrm_netlink_rcv+0x77/0xc0 netlink_unicast+0xe90/0x1280 netlink_sendmsg+0x126d/0x1490 __sock_sendmsg+0x332/0x3d0 ____sys_sendmsg+0x863/0xc30 ___sys_sendmsg+0x285/0x3e0 __x64_sys_sendmsg+0x2d6/0x560 x64_sys_call+0x1316/0x3cc0 do_syscall_64+0xd8/0x1c0 entry_SYSCALL_64_after_hwframe+0x79/0x81 Uninit was created at: __kmalloc+0x571/0xd30 attach_auth+0x106/0x3e0 xfrm_add_sa+0x2aa0/0x4230 xfrm_user_rcv_msg+0x832/0xc00 netlink_rcv_skb+0x613/0x780 xfrm_netlink_rcv+0x77/0xc0 netlink_unicast+0xe90/0x1280 netlink_sendmsg+0x126d/0x1490 __sock_sendmsg+0x332/0x3d0 ____sys_sendmsg+0x863/0xc30 ___sys_sendmsg+0x285/0x3e0 __x64_sys_sendmsg+0x2d6/0x560 x64_sys_call+0x1316/0x3cc0 do_syscall_64+0xd8/0x1c0 entry_SYSCALL_64_after_hwframe+0x79/0x81 Bytes 328-379 of 732 are uninitialized Memory access of size 732 starts at ffff88800e18e000 Data copied to user address 00007ff30f48aff0 CPU: 2 PID: 18167 Comm: syz-executor.0 Not tainted 6.8.11 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 Fixes copying of xfrm algorithms where some random data of the structure fields can end up in userspace. Padding in structures may be filled with random (possibly sensitve) data and should never be given directly to user-space. A similar issue was resolved in the commit 8222d5910dae ("xfrm: Zero padding when dumping algos and encap") Found by Linux Verification Center (linuxtesting.org) with Syzkaller.
CWE:   CWE-908: Use of Uninitialized Resource
CVSS Source:   NVD
CVSS Base score:   5.5
CVSS Vector:   (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N)

CVEID:   CVE-2024-50142
DESCRIPTION:   In the Linux kernel, the following vulnerability has been resolved: xfrm: validate new SA's prefixlen using SA family when sel.family is unset This expands the validation introduced in commit 07bf7908950a ("xfrm: Validate address prefix lengths in the xfrm selector.") syzbot created an SA with usersa.sel.family = AF_UNSPEC usersa.sel.prefixlen_s = 128 usersa.family = AF_INET Because of the AF_UNSPEC selector, verify_newsa_info doesn't put limits on prefixlen_{s,d}. But then copy_from_user_state sets x->sel.family to usersa.family (AF_INET). Do the same conversion in verify_newsa_info before validating prefixlen_{s,d}, since that's how prefixlen is going to be used later on.
CVSS Source:   NVD
CVSS Base score:   5.5
CVSS Vector:   (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)

CVEID:   CVE-2024-50192
DESCRIPTION:   In the Linux kernel, the following vulnerability has been resolved: irqchip/gic-v4: Don't allow a VMOVP on a dying VPE Kunkun Jiang reported that there is a small window of opportunity for userspace to force a change of affinity for a VPE while the VPE has already been unmapped, but the corresponding doorbell interrupt still visible in /proc/irq/. Plug the race by checking the value of vmapp_count, which tracks whether the VPE is mapped ot not, and returning an error in this case. This involves making vmapp_count common to both GICv4.1 and its v4.0 ancestor.
CVSS Source:   NVD
CVSS Base score:   4.7
CVSS Vector:   (CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H)

CVEID:   CVE-2024-50256
DESCRIPTION:   Linux Kernel is vulnerable to a denial of service, caused by a crash in nf_send_reset6(). A local authenticated attacker could exploit this vulnerability to cause a denial of service.
CVSS Source:   IBM X-Force
CVSS Base score:   5.5
CVSS Vector:   (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)

CVEID:   CVE-2024-50264
DESCRIPTION:   In the Linux kernel, the following vulnerability has been resolved: vsock/virtio: Initialization of the dangling pointer occurring in vsk->trans During loopback communication, a dangling pointer can be created in vsk->trans, potentially leading to a Use-After-Free condition. This issue is resolved by initializing vsk->trans to NULL.
CWE:   CWE-416: Use After Free
CVSS Source:   NVD
CVSS Base score:   7.8
CVSS Vector:   (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H)

CVEID:   CVE-2024-26935
DESCRIPTION:   Linux Kernel is vulnerable to a denial of service, caused by an error related to unremoved procfs host directory regression. A local authenticated attacker could exploit this vulnerability to cause a denial of service.
CWE:   CWE-770: Allocation of Resources Without Limits or Throttling
CVSS Source:   IBM X-Force
CVSS Base score:   5.5
CVSS Vector:   (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)

CVEID:   CVE-2024-50275
DESCRIPTION:   In the Linux kernel, the following vulnerability has been resolved: arm64/sve: Discard stale CPU state when handling SVE traps The logic for handling SVE traps manipulates saved FPSIMD/SVE state incorrectly, and a race with preemption can result in a task having TIF_SVE set and TIF_FOREIGN_FPSTATE clear even though the live CPU state is stale (e.g. with SVE traps enabled). This has been observed to result in warnings from do_sve_acc() where SVE traps are not expected while TIF_SVE is set: | if (test_and_set_thread_flag(TIF_SVE)) | WARN_ON(1); /* SVE access shouldn't have trapped */ Warnings of this form have been reported intermittently, e.g. https://lore.kernel.org/linux-arm-kernel/CA+G9fYtEGe_DhY2Ms7+L7NKsLYUomGsgqpdBj+QwDLeSg=JhGg@mail.gmail.com/ https://lore.kernel.org/linux-arm-kernel/000000000000511e9a060ce5a45c@google.com/ The race can occur when the SVE trap handler is preempted before and after manipulating the saved FPSIMD/SVE state, starting and ending on the same CPU, e.g. | void do_sve_acc(unsigned long esr, struct pt_regs *regs) | { | // Trap on CPU 0 with TIF_SVE clear, SVE traps enabled | // task->fpsimd_cpu is 0. | // per_cpu_ptr(&fpsimd_last_state, 0) is task. | | ... | | // Preempted; migrated from CPU 0 to CPU 1. | // TIF_FOREIGN_FPSTATE is set. | | get_cpu_fpsimd_context(); | | if (test_and_set_thread_flag(TIF_SVE)) | WARN_ON(1); /* SVE access shouldn't have trapped */ | | sve_init_regs() { | if (!test_thread_flag(TIF_FOREIGN_FPSTATE)) { | ... | } else { | fpsimd_to_sve(current); | current->thread.fp_type = FP_STATE_SVE; | } | } | | put_cpu_fpsimd_context(); | | // Preempted; migrated from CPU 1 to CPU 0. | // task->fpsimd_cpu is still 0 | // If per_cpu_ptr(&fpsimd_last_state, 0) is still task then: | // - Stale HW state is reused (with SVE traps enabled) | // - TIF_FOREIGN_FPSTATE is cleared | // - A return to userspace skips HW state restore | } Fix the case where the state is not live and TIF_FOREIGN_FPSTATE is set by calling fpsimd_flush_task_state() to detach from the saved CPU state. This ensures that a subsequent context switch will not reuse the stale CPU state, and will instead set TIF_FOREIGN_FPSTATE, forcing the new state to be reloaded from memory prior to a return to userspace.
CVSS Source:   NVD
CVSS Base score:   7
CVSS Vector:   (CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H)

CVEID:   CVE-2024-3661
DESCRIPTION:   DHCP can add routes to a client’s routing table via the classless static route option (121). VPN-based security solutions that rely on routes to redirect traffic can be forced to leak traffic over the physical interface. An attacker on the same local network can read, disrupt, or possibly modify network traffic that was expected to be protected by the VPN.
CWE:   CWE-306: Missing Authentication for Critical Function
CVSS Source:   NVD
CVSS Base score:   7.6
CVSS Vector:   (CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L)

CVEID:   CVE-2024-53088
DESCRIPTION:   In the Linux kernel, the following vulnerability has been resolved: i40e: fix race condition by adding filter's intermediate sync state Fix a race condition in the i40e driver that leads to MAC/VLAN filters becoming corrupted and leaking. Address the issue that occurs under heavy load when multiple threads are concurrently modifying MAC/VLAN filters by setting mac and port VLAN. 1. Thread T0 allocates a filter in i40e_add_filter() within i40e_ndo_set_vf_port_vlan(). 2. Thread T1 concurrently frees the filter in __i40e_del_filter() within i40e_ndo_set_vf_mac(). 3. Subsequently, i40e_service_task() calls i40e_sync_vsi_filters(), which refers to the already freed filter memory, causing corruption. Reproduction steps: 1. Spawn multiple VFs. 2. Apply a concurrent heavy load by running parallel operations to change MAC addresses on the VFs and change port VLANs on the host. 3. Observe errors in dmesg: "Error I40E_AQ_RC_ENOSPC adding RX filters on VF XX, please set promiscuous on manually for VF XX". Exact code for stable reproduction Intel can't open-source now. The fix involves implementing a new intermediate filter state, I40E_FILTER_NEW_SYNC, for the time when a filter is on a tmp_add_list. These filters cannot be deleted from the hash list directly but must be removed using the full process.
CWE:   CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
CVSS Source:   NVD
CVSS Base score:   4.7
CVSS Vector:   (CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H)

CVEID:   CVE-2024-53122
DESCRIPTION:   In the Linux kernel, the following vulnerability has been resolved: mptcp: cope racing subflow creation in mptcp_rcv_space_adjust Additional active subflows - i.e. created by the in kernel path manager - are included into the subflow list before starting the 3whs. A racing recvmsg() spooling data received on an already established subflow would unconditionally call tcp_cleanup_rbuf() on all the current subflows, potentially hitting a divide by zero error on the newly created ones. Explicitly check that the subflow is in a suitable state before invoking tcp_cleanup_rbuf().
CWE:   CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
CVSS Source:   NVD
CVSS Base score:   5.5
CVSS Vector:   (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)