CVE-2026-12665: IBM MQ could allow a remote attacker to execute arbitrary code due to a stack buffer overflow when processing

Routine

HIGH 8.1REMOTEUPGRADEDOWNGRADE

CVE-2026-12665 is a high-severity flaw (CVSS 8.1) affecting mq operator, supplied mq advanced container images. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

High severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	8.1 (High)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	None
User interaction	None
EPSS exploit chance	0.3% (top 84%)
CISA exploited list	No
Weakness	CWE-121
Published	2026-10-19
Last modified	2026-10-23

Publisher (CNA): IBM Corporation · Vendor: ibm

Last updated 2026-10-23 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-10-19 17:17 UTCPublished CVE record published
2026-10-23 17:21 UTCUpdated Record last modified

ibm mq operator UPGRADE

Affected: >= 2.0.0 and <= 2.0.29 · >= 3.2.0 and <= 3.2.29 · 3.3.0 · 3.4.0 · 3.4.1 · 3.5.0 · 3.5.1 · 3.5.2

Fixed in: newer than 3.2.29

Safe to downgrade to: a release before 2.0.0

1. Check installed version

apt-cache policy mq-operator || rpm -q mq-operator || mq-operator --version

2. UPGRADE to newer than 3.2.29 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade mq-operator

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade mq-operator

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 2.0.0 (Debian / Ubuntu)

apt-cache madison mq-operator sudo apt install mq-operator=<VERSION_BEFORE_2.0.0> sudo apt-mark hold mq-operator

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list mq-operator sudo dnf downgrade mq-operator-<VERSION_BEFORE_2.0.0> sudo dnf versionlock add mq-operator

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

ibm supplied mq advanced container images DOWNGRADE

Affected: 9.4.1.0 r1 · 9.4.1.0 r2 · 9.4.1.1 r1 · 9.4.2.0 r1 · 9.4.2.0 r2 · 9.4.2.1 r1 · 9.4.2.1 r2 · 9.4.3.0 r1

Fixed in: no fixed release known

Safe to downgrade to: a release before 9.3.0.0

1. Check installed version

apt-cache policy supplied-mq-advanced-container-images || rpm -q supplied-mq-advanced-container-images || supplied-mq-advanced-container-images --version

2. No fixed release: DOWNGRADE to a release before 9.3.0.0 (Debian / Ubuntu)

apt-cache madison supplied-mq-advanced-container-images sudo apt install supplied-mq-advanced-container-images=<VERSION_BEFORE_9.3.0.0> sudo apt-mark hold supplied-mq-advanced-container-images

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list supplied-mq-advanced-container-images sudo dnf downgrade supplied-mq-advanced-container-images-<VERSION_BEFORE_9.3.0.0> sudo dnf versionlock add supplied-mq-advanced-container-images

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Exact fixes by distribution

A distro patch exists: prefer upgrading over downgrading.

Fedora 46 · wasmedge · FIXED · 0.18.1-1.fc46 · FEDORA-2026-4c27216e39 · source

sudo dnf upgrade --advisory=FEDORA-2026-4c27216e39

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-12665?

mq operator: upgrade to newer than 3.2.29; supplied mq advanced container images: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2026-12665 being exploited?

CVE-2026-12665 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-12665 affect?

CVE-2026-12665 affects mq operator, supplied mq advanced container images. Severity is high (CVSS 8.1). 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.

How urgent is CVE-2026-12665?

Priority 37/100. High severity; Remotely exploitable, no login, no user action

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References

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