Security Bulletin
Summary
gRPC is affected by denial of service and connection termination issues due to flaws in request parsing and protocol handling. These issues may result in excessive resource consumption or unexpected disruptions in service availability.
Vulnerability Details
CVEID: CVE-2023-33953
DESCRIPTION: gRPC contains a vulnerability that allows hpack table accounting errors could lead to unwanted disconnects between clients and servers in exceptional cases/ Three vectors were found that allow the following DOS attacks:
- Unbounded memory buffering in the HPACK parser
- Unbounded CPU consumption in the HPACK parser
The unbounded CPU consumption is down to a copy that occurred per-input-block in the parser, and because that could be unbounded due to the memory copy bug we end up with an O(n^2) parsing loop, with n selected by the client.
The unbounded memory buffering bugs:
- The header size limit check was behind the string reading code, so we needed to first buffer up to a 4 gigabyte string before rejecting it as longer than 8 or 16kb.
- HPACK varints have an encoding quirk whereby an infinite number of 0’s can be added at the start of an integer. gRPC’s hpack parser needed to read all of them before concluding a parse.
- gRPC’s metadata overflow check was performed per frame, so that the following sequence of frames could cause infinite buffering: HEADERS: containing a: 1 CONTINUATION: containing a: 2 CONTINUATION: containing a: 3 etc…
CWE: CWE-789: Memory Allocation with Excessive Size Value
CVSS Source: IBM X-Force
CVSS Base score: 7.5
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
CVEID: CVE-2023-44487
DESCRIPTION: The HTTP/2 protocol allows a denial of service (server resource consumption) because request cancellation can reset many streams quickly, as exploited in the wild in August through October 2023.
CWE: CWE-400: Uncontrolled Resource Consumption
CVSS Source: IBM X-Force
CVSS Base score: 7.5
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
CVEID: CVE-2023-32732
DESCRIPTION: gRPC contains a vulnerability whereby a client can cause a termination of connection between a HTTP2 proxy and a gRPC server: a base64 encoding error for `-bin` suffixed headers will result in a disconnection by the gRPC server, but is typically allowed by HTTP2 proxies. We recommend upgrading beyond the commit in https://github.com/grpc/grpc/pull/32309 https://www.google.com/url
CWE: CWE-440: Expected Behavior Violation
CVSS Source: IBM X-Force
CVSS Base score: 5.3
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L)
Affected Products and Versions
| Affected Product(s) | Version(s) |
| IBM QRadar SIEM | 7.5 - 7.5.0 UP12 IF02 |
Remediation/Fixes
| Product | Version | Fix |
| IBM QRadar SIEM | 7.5.0 | 7.5.0 QRadar Protocol GoogleCloudPubSub |
| IBM QRadar SIEM | 7.5.0 | 7.5.0 QRadar Protocol GoogleCommon |
| IBM QRadar SIEM | 7.5.0 | 7.5.0 QRadar Protocol GoogleGSuiteActivityReportsRESTAPI |
Workarounds and Mitigations
Please be aware that these updates are available via Auto Update if you have it enabled.
Get Notified about Future Security Bulletins
References
Acknowledgement
Change History
15 Jul 2025: Initial Publication
*The CVSS Environment Score is customer environment specific and will ultimately impact the Overall CVSS Score. Customers can evaluate the impact of this vulnerability in their environments by accessing the links in the Reference section of this Security Bulletin.
Disclaimer
According to the Forum of Incident Response and Security Teams (FIRST), the Common Vulnerability Scoring System (CVSS) is an "industry open standard designed to convey vulnerability severity and help to determine urgency and priority of response." IBM PROVIDES THE CVSS SCORES ""AS IS"" WITHOUT WARRANTY OF ANY KIND, INCLUDING THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. CUSTOMERS ARE RESPONSIBLE FOR ASSESSING THE IMPACT OF ANY ACTUAL OR POTENTIAL SECURITY VULNERABILITY. In addition to other efforts to address potential vulnerabilities, IBM periodically updates the record of components contained in our product offerings. As part of that effort, if IBM identifies previously unidentified packages in a product/service inventory, we address relevant vulnerabilities regardless of CVE date. Inclusion of an older CVEID does not demonstrate that the referenced product has been used by IBM since that date, nor that IBM was aware of a vulnerability as of that date. We are making clients aware of relevant vulnerabilities as we become aware of them. "Affected Products and Versions" referenced in IBM Security Bulletins are intended to be only products and versions that are supported by IBM and have not passed their end-of-support or warranty date. Thus, failure to reference unsupported or extended-support products and versions in this Security Bulletin does not constitute a determination by IBM that they are unaffected by the vulnerability. Reference to one or more unsupported versions in this Security Bulletin shall not create an obligation for IBM to provide fixes for any unsupported or extended-support products or versions.
Document Location
Worldwide
Was this topic helpful?
Document Information
Modified date:
15 July 2025
UID
ibm17239753