CVE-2026-29111: systemd, a system and service manager, (as PID 1) hits an assert and freezes execution when an unprivileged IP

Q: How do I fix CVE-2026-29111?

systemd: upgrade to 257.11, 258.5, 259.2. Exact commands for each OS are on this page.

Q: Is CVE-2026-29111 being exploited?

CVE-2026-29111 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-29111 affect?

CVE-2026-29111 affects systemd. Severity is medium (CVSS 5.5). systemd, a system and service manager, (as PID 1) hits an assert and freezes execution when an unprivileged IPC API call is made with spurious data. On version v249 and older the effect is not an assert, but stack overwriting, with the atta

Q: How urgent is CVE-2026-29111?

Priority 20/100. No elevated risk signals yet.

Routine

MEDIUM 5.5UPGRADE

CVE-2026-29111 is a medium-severity flaw (CVSS 5.5) affecting systemd. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

systemd, a system and service manager, (as PID 1) hits an assert and freezes execution when an unprivileged IPC API call is made with spurious data. On version v249 and older the effect is not an assert, but stack overwriting, with the attacker controlled content. From version v250 and newer this is not possible as the safety check causes an assert instead. This IPC call was added in v239, so versions older than that are not affected. Versions 26

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	5.5 (Medium)
Attack vector	Local
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.1% (top 98%)
CISA exploited list	No
Weakness	CWE-269
Published	2026-03-23
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: systemd project

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-03-23 22:16 UTCPublished CVE record published
2026-06-17 10:29 UTCUpdated Record last modified

systemd project systemd UPGRADE

Affected: >= 239 and < 257.11 · >= 258 and < 258.5 · >= 259 and < 259.2

Fixed in: 257.11, 258.5, 259.2

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy systemd || rpm -q systemd || systemd --version

2. UPGRADE to 257.11 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade systemd

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade systemd

Note

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

Advisories and coverage

Official advisories

AlmaLinux Errata: [ALSA-2026:19213] Moderate: systemd security update 2026-05-26

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-2026-29111?

systemd: upgrade to 257.11, 258.5, 259.2. Exact commands for each OS are on this page.

Is CVE-2026-29111 being exploited?

CVE-2026-29111 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-2026-29111 affect?

CVE-2026-29111 affects systemd. Severity is medium (CVSS 5.5). systemd, a system and service manager, (as PID 1) hits an assert and freezes execution when an unprivileged IPC API call is made with spurious data. On version v249 and older the effect is not an assert, but stack overwriting, with the atta

How urgent is CVE-2026-29111?

Priority 20/100. No elevated risk signals yet.

References

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