Security Bulletin
Summary
CVE-2026-3592: Resolver queries a specially crafted zone containing self-pointed glue records, causing disproportionate resource consumption. CVE-2026-5946: Specially crafted DNS messages using non-IN classes (e.g., CHAOS, HESIOD, ANY, NONE) trigger assertion failures, terminating the named process.
Vulnerability Details
CVEID: CVE-2026-3592
DESCRIPTION: BIND resolvers are vulnerable to an amplified resource consumption/exhaustion attack. If a victim resolver makes a query to a specially crafted zone, the resolver will consume disproportionate resources.
This issue affects BIND 9 versions 9.11.0 through 9.16.50, 9.18.0 through 9.18.48, 9.20.0 through 9.20.22, 9.21.0 through 9.21.21, 9.11.3-S1 through 9.16.50-S1, 9.18.11-S1 through 9.18.48-S1, and 9.20.9-S1 through 9.20.22-S1.
CWE: CWE-408: Incorrect Behavior Order: Early Amplification
CVSS Source: security-officer@isc.org
CVSS Base score: 5.3
CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L)
CVEID: CVE-2026-5946
DESCRIPTION: Multiple flaws have been identified in `named` related to the handling of DNS messages whose CLASS is not Internet (`IN`) — for example, `CHAOS` or `HESIOD`, or DNS messages that specify meta-classes (`ANY` or `NONE`) in the question section. Specially crafted requests reaching the affected code paths — recursion, dynamic updates (`UPDATE`), zone change notifications (`NOTIFY`), or processing of `IN`-specific record types in non-`IN` data — can cause assertion failures in `named`.
This issue affects BIND 9 versions 9.11.0 through 9.16.50, 9.18.0 through 9.18.48, 9.20.0 through 9.20.22, 9.21.0 through 9.21.21, 9.11.3-S1 through 9.16.50-S1, 9.18.11-S1 through 9.18.48-S1, and 9.20.9-S1 through 9.20.22-S1.
CWE: CWE-20: Improper Input Validation
CVSS Source: security-officer@isc.org
CVSS Base score: 7.5
CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
Affected Products and Versions
| Affected Product(s) | Version(s) |
| AIX | 7.3 |
| AIX | 7.2 |
| VIOS | 4.1 |
The vulnerabilities are being addressed in the following filesets:
key_fileset = aix
Fileset Lower Level Upper Level KEY
----------------------------------------------------------
bind.rte 7.1.916.0 7.1.916.4800 key_w_fs
bind.rte 7.2.916.0 7.2.916.4801 key_w_fs
bind.rte 7.2.918.0 7.2.918.2802 key_w_fs
bind.rte 7.3.916.0 7.3.916.4800 key_w_fs
bind.rte 7.3.918.0 7.3.918.2802 key_w_fs
Note:
A. Latest level of BIND fileset is available from the web download site:
https://www.ibm.com/resources/mrs/assets?source=aixbp
To find out whether the affected filesets are installed
on your systems, refer to the lslpp command found in AIX user's guide.
Example: lslpp -L | grep -i bind.rte
Remediation/Fixes
IBM strongly recommends addressing the vulnerability now.
The AIX and VIOS fixes can be downloaded via https from:
https://aix.software.ibm.com/aix/efixes/security/bind_fix30.tar
The fileset update has a dependency on OpenSSL 3.0. OpenSSL 3.0 may
be downloaded from:
https://www.ibm.com/resources/mrs/assets?source=aixbp
The link above is to a tar file containing this signed
advisory, install packages, and OpenSSL signatures for each
package. The fixes below include prerequisite checking. This will
enforce the correct mapping between the fixes and AIX
Technology Levels.
To extract the fixes from the tar file:
tar xvf bind_fix30.tar
For AIX 7.2 (requires OpenSSL 3.0):
tar xvf bind_fix30/72bind918.tar
For AIX 7.3 and VIOS 4.1:
tar xvf bind_fix30/73bind918.tar
IMPORTANT: If possible, it is recommended that a mksysb backup
of the system be created. Verify it is both bootable and
readable before proceeding.
To preview the fix installation:
installp -apYd . bind
To install the fix package:
installp -aXYd . bind
Verify you have retrieved the fixes intact:
The checksums below were generated using the
"openssl dgst -sha256 [file]" command as the following:
openssl dgst -sha256 filename KEY
---------------------------------------------------------------------------------------
4981af0a108a6d3d2ad9fac7738ffe05c00b3e045d9b90e3b2280bd3df088946 72bind.rte key_w_csum
4e8ae1957564c90e495cad785fe42a1223ddb4186f120db07770fde68f455e9c 73bind.rte key_w_csum
openssl dgst -sha512 filename
----------------------------------------------------------------------------------------------------------------------------------------------------------
379fed277de0f554de1a0caf72781296a6b848e1e8d7775577071054f070362c2371d27b8e114f539f0b176ce6a540789b0cc7b13f72a62a87d3076ae7a7e8f3 72bind.rte key_4K_w_csum
46d6266cdae6fb44d86bf14578be1f6fc61409389d1dac211330e52c2043e70e44983179b440dad3bd2bbf53b5a3a925f3a5efd58dbe62e2488bc8bd22d28dc2 73bind.rte key_4K_w_csum
These sums should match exactly. The OpenSSL signatures in the tar
file and on this advisory can also be used to verify the
integrity of the fixes. If the sums or signatures cannot be
confirmed, contact IBM Support at
http://ibm.com/support/ and describe the discrepancy.
openssl dgst -sha256 -verify [pubkey_file] -signature [advisory_file].sig [advisory_file]
openssl dgst -sha256 -verify [pubkey_file] -signature [ifix_file].sig [ifix_file]
Published advisory OpenSSL signature file location:
https://aix.software.ibm.com/aix/efixes/security/bind_advisory30.asc.sig
B. FIX AND INTERIM FIX INSTALLATION
If possible, it is recommended that a mksysb backup of the system
be created. Verify it is both bootable and readable before
proceeding.
To preview a fix installation:
installp -a -d fix_name -p all # where fix_name is the name of the
# fix package being previewed.
To install a fix package:
installp -a -d fix_name -X all # where fix_name is the name of the
# fix package being installed.
Interim fixes have had limited functional and regression
testing but not the full regression testing that takes place
for Service Packs; however, IBM does fully support them.
Interim fix management documentation can be found at:
https://www.ibm.com/support/pages/managing-interim-fixes-aix
To preview an interim fix installation:
emgr -e ipkg_name -p # where ipkg_name is the name of the
# interim fix package being previewed.
To install an interim fix package:
emgr -e ipkg_name -X # where ipkg_name is the name of the
# interim fix package being installed.
Workarounds and Mitigations
None
Get Notified about Future Security Bulletins
References
Acknowledgement
Change History
03 Jul 2026: 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
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Document Information
Modified date:
03 July 2026
Initial Publish date:
03 July 2026
UID
ibm17279039