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VulnerabilityPublished Updated

CVE-2025-21834: Linux kernel · seccomp: passthrough uretprobe systemcall without filtering

Affects Linux kernelSource GCVE Database

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Not known to be exploited · CVSS 5.5 Medium · fixed in 6.11.0-21.21~24.04.1 : update Linux kernel when convenient.

Data as of 29 Oct 2026, 23:41 UTC

CVSS 3.1 base score
5.5Medium
How severe the flaw is on the 0–10 CVSS scale.
Patch
Available – fixed in 6.11.0-21.21~24.04.1, 6.11.0-1017.17
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 6 Mar 2025

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.

What to do

Upgrade the Ubuntu to 6.11.0-21.21~24.04.1 (linux-hwe-6.11 package) or 6.11.0-1017.17 (linux-oem-6.11 package).

Affected software

ProductAffectedFixed in
Ubuntu 24.04 LTSlinux-hwe-6.11pkg:deb/ubuntu/linux-hwe-6.11?arch=source&distro=nobleOther threatsAffected
  • <6.11.0-21.21~24.04.1
Fixed in
  • 6.11.0-21.21~24.04.1
Ubuntu 24.04 LTSlinux-oem-6.11pkg:deb/ubuntu/linux-oem-6.11?arch=source&distro=nobleOther threatsAffected
  • <6.11.0-1017.17
Fixed in
  • 6.11.0-1017.17
Ubuntu 24.04 LTSlinux-raspi-realtimepkg:deb/ubuntu/linux-raspi-realtime?arch=source&distro=nobleOther threatsAffected
  • =6.8.0-2019.20
Fixed in–
Ubuntu 22.04 LTSlinux-allwinner-5.19pkg:deb/ubuntu/linux-allwinner-5.19?arch=source&distro=jammyOther threatsAffected
  • 5.19.0-1007.7~22.04.1 – 5.19.0-1015.15~22.04.1
8 affected builds
Fixed in–
Ubuntu 22.04 LTSlinux-aws-5.19pkg:deb/ubuntu/linux-aws-5.19?arch=source&distro=jammyOther threatsAffected
  • 5.19.0-1019.20~22.04.1 – 5.19.0-1029.30~22.04.1
10 affected builds
Fixed in–
Ubuntu 22.04 LTSlinux-aws-6.2pkg:deb/ubuntu/linux-aws-6.2?arch=source&distro=jammyOther threatsAffected
  • 6.2.0-1005.5~22.04.1 – 6.2.0-1018.18~22.04.1
14 affected builds
Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A patch is available and included in Linux kernel versions 6.11.0-21.21~24.04.1, 6.11.0-1017.17, and later. Users should update to these fixed kernel versions to resolve the issue. Since the fix allows the uretprobe syscall to pass through seccomp filters unconditionally, no additional configuration changes are required. No other mitigation actions are necessary.

Description

A vulnerability in the Linux kernel seccomp subsystem allowed the passthrough of the uretprobe system call without filtering. This caused processes running inside Docker or other userspace applications using seccomp to segfault when encountering the uretprobe return probe, as the default seccomp filters blocked this syscall. The issue arises because uretprobe is a kernel implementation detail not typically allowed by default in seccomp filters. The vulnerability has been fixed by allowing this syscall to pass through seccomp unconditionally. The fix is included in Linux kernel versions 6.11.0-21.21~24.04.1 and 6.11.0-1017.17 and later.

References

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