CVE-2026-29111
Received Received - Intake
Stack Overflow in systemd IPC Causes PID 1 Crash or Freeze

Publication date: 2026-03-23

Last updated on: 2026-04-15

Assigner: GitHub, Inc.

Description
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 260-rc1, 259.2, 258.5, and 257.11 contain patches. No known workarounds are available.
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Meta Information
Published
2026-03-23
Last Modified
2026-04-15
Generated
2026-06-16
AI Q&A
2026-03-24
EPSS Evaluated
2026-06-15
NVD
CVE-2026-29111
Affected Vendors & Products
Showing 3 associated CPEs
Vendor Product Version / Range
systemd_project systemd From 239 (inc) to 257.11 (exc)
systemd_project systemd From 258 (inc) to 258.5 (exc)
systemd_project systemd From 259 (inc) to 259.2 (exc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-269 The product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor.
Attack-Flow Graph
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Executive Summary

This vulnerability affects systemd, a system and service manager running as PID 1. When an unprivileged IPC API call is made with spurious (malformed or unexpected) data, systemd either hits an assert and freezes execution or, in older versions, experiences stack overwriting with attacker-controlled content.

Specifically, in versions up to v249, the vulnerability allows stack overwriting, which means an attacker can overwrite parts of the systemd process stack with their own data. From version v250 onwards, a safety check causes an assert failure instead, which freezes systemd but prevents stack corruption.

This IPC call was introduced in version v239, so versions older than that are not affected. Several patched versions (260-rc1, 259.2, 258.5, and 257.11) have addressed this issue. No known workarounds are available.

Impact Analysis

The vulnerability can cause systemd, the core system and service manager, to freeze or have its stack overwritten by attacker-controlled data. This can lead to a denial of service (DoS) condition where the system becomes unresponsive.

Because systemd runs as PID 1, its failure can halt or severely disrupt the entire system's operation, potentially requiring a reboot or manual intervention.

The CVSS score of 5.5 indicates a medium severity impact, with the main impact being availability (A:H), meaning the system's availability is highly affected.

Compliance Impact

I don't know

Detection Guidance

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Mitigation Strategies

To mitigate this vulnerability, you should update systemd to a patched version. Versions 260-rc1, 259.2, 258.5, and 257.11 contain patches that address this issue.

No known workarounds are available, so applying the update is the immediate recommended action.

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