CyberSecBulletin
CVE-2026-12665NVD status: Analyzed

MQ Operator: Stack-based Buffer Overflow

Published Updated By the CyberSecBulletin desk

CVE-2026-12665 is a critical-severity stack-based buffer overflow vulnerability in MQ Operator from IBM, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 3.4.0 as the first without the flaw, so updating MQ Operator to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.32% chance of exploitation within 30 days, which is low compared with other CVEs.

Patch this week

Critical severity: a successful attack would have severe impact.

What to do

  1. Update MQ Operator to 3.4.0 or a later version.
  2. Read the advisory on ibm.com for workarounds and exact fixed builds.
  3. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
IBMMQ Operator3.2.0 through 3.2.29; 3.3.0 up to, but not including, 3.4.0; 3.4.1; 3.5.0; 3.5.1 through 3.5.3; 3.6.0 through 3.6.4; 3.7.0 through 3.7.2; 3.8.0; and 10 more ranges3.4.0
IBMMQ Advanced container images9.4.0.6-r1; 9.4.0.6-r2; 9.4.0.7-r1; 9.4.0.10-r1; 9.4.0.10-r2; 9.4.0.11-r1; 9.4.0.11-r2; 9.4.0.11-r3; and 32 more rangesNot stated
IBMSupplied Mq Advanced Container Images9.4.1.0; 9.4.1.1; 9.4.2.0; 9.4.2.1; 9.4.3.0; 9.4.3.1; 9.4.4.0; 9.4.4.1; and 32 more rangesNot stated

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.18.1HighCNA (us.ibm.com)
CVSS 3.19.8CriticalNVD

Official description

IBM MQ could allow a remote attacker to execute arbitrary code due to a stack buffer overflow when processing TLS certificates with malformed distinguished names during channel connection establishment.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Stack-based Buffer Overflow

The product writes past the end of a buffer that was allocated on the stack.

How developers prevent this class of flaw

  • Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND discusses canary-based detection in detail.
  • Use an abstraction library to abstract away risky APIs. Not a complete solution.
  • Implement and perform bounds checking on input.

More Stack-based Buffer Overflow vulnerabilities (CWE-121)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in MQ Operator

All MQ Operator vulnerabilities

Recent Stack-based Buffer Overflow vulnerabilities

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