CVE-2025-21834

Process crash via seccomp-filtered uretprobe syscall

Published Mar 6, 2025 · Updated May 11, 2026

Availability flaw in Linux kernel 6.11 allows local users to crash seccomp-confined processes by attaching uretprobes. kernel/seccomp.c subjects the kernel-injected uretprobe system call to user-space seccomp filters, which reject its unknown syscall number and terminate the traced process. The condition is limited to x86_64 systems where a uretprobe is attached to a process governed by an allowlist-style seccomp policy.

CVSS severity5.5
Medium
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Availability flaw in Linux kernel 6.11 allows local users to crash seccomp-confined processes by attaching uretprobes. kernel/seccomp.c subjects the kernel-injected uretprobe system call to user-space seccomp filters, which reject its unknown syscall number and terminate the traced process. The condition is limited to x86_64 systems where a uretprobe is attached to a process governed by an allowlist-style seccomp policy.

The record

CVE
CVE-2025-21834
Published
Mar 6, 2025
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 6, 2025CVE publishedPublication date reported by the CVE source.
  2. May 11, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=6.11
  2. Affected versionversion=ff474a78cef5cb5f32be52fe25b78441327a2e7c <5a262628f4cf2437d863fe41f9d427177b87664c
  3. Affected versionversion=ff474a78cef5cb5f32be52fe25b78441327a2e7c <cf6cb56ef24410fb5308f9655087f1eddf4452e6
  4. Affected versionversion=ff474a78cef5cb5f32be52fe25b78441327a2e7c <fa80018aa5be10c35e9fa896b7b4061a8dce3eed

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=6.11; version=ff474a78cef5cb5f32be52fe25b78441327a2e7c <5a262628f4cf2437d863fe41f9d427177b87664c; version=ff474a78cef5cb5f32be52fe25b78441327a2e7c <cf6cb56ef24410fb5308f9655087f1eddf4452e6; version=ff474a78cef5cb5f32be52fe25b78441327a2e7c <fa80018aa5be10c35e9fa896b7b4061a8dce3eed

Published CVSS scores

5.5UbuntuCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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