CVE-2026-53163

Local denial of service via unarmed waiter

Published Jun 25, 2026 · Updated Jun 25, 2026

NULL pointer dereference in the Linux Kernel rtmutex subsystem allows local users to crash the system via FUTEX_CMP_REQUEUE_PI. During deadlock detection, task_blocks_on_rt_mutex() leaves waiter->task null, but rt_mutex_start_proxy_lock() still calls remove_waiter() after successful lock acquisition. A local low-privileged process must invoke the priority-inheritance futex requeue path; the resulting null dereference interrupts system availability without reported data exposure or modification.

CVSS severity5.5
Medium
EPSS probability0.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in the Linux Kernel rtmutex subsystem allows local users to crash the system via FUTEX_CMP_REQUEUE_PI. During deadlock detection, task_blocks_on_rt_mutex() leaves waiter->task null, but rt_mutex_start_proxy_lock() still calls remove_waiter() after successful lock acquisition. A local low-privileged process must invoke the priority-inheritance futex requeue path; the resulting null dereference interrupts system availability without reported data exposure or modification.

The record

CVE
CVE-2026-53163
Published
Jun 25, 2026
Updated
Jun 25, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-476
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 25, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 25, 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=3bfdc63936dd4773109b7b8c280c0f3b5ae7d349 <40a25d59e85b3c8709ac2424d44f65610467871e
  2. Affected versionversion=3fb7394a837740770f0d6b4b30567e60786a63f2 <a388e3dfaf9538a680de5ed43a8ebb5dd45b6e53
  3. Affected versionversion=6.1.175 <6.2
  4. Affected versionversion=6.12.86 <6.13
  5. Affected versionversion=6.18.27 <6.18.36
  6. Affected versionversion=6.6.140 <6.7
  7. Affected versionversion=6d52dfcb2a5db86e346cf51f8fcf2071b8085166
  8. Affected versionversion=7.0.4 <7.0.13
  9. Affected versionversion=88614876370aac8ad1050ad785a4c095ba17ac11 <55363fa0a04524d11efeaadee734d2db1756ed27
  10. Affected versionversion=8a1fc8d698ac5e5916e3082a0f74450d71f9611f
  11. Affected versionversion=d8cce4773c2b23d819baf5abedc62f7b430e8745

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=3bfdc63936dd4773109b7b8c280c0f3b5ae7d349 <40a25d59e85b3c8709ac2424d44f65610467871e; version=3fb7394a837740770f0d6b4b30567e60786a63f2 <a388e3dfaf9538a680de5ed43a8ebb5dd45b6e53; version=6.1.175 <6.2; version=6.12.86 <6.13; version=6.18.27 <6.18.36; version=6.6.140 <6.7; version=6d52dfcb2a5db86e346cf51f8fcf2071b8085166; version=7.0.4 <7.0.13; version=88614876370aac8ad1050ad785a4c095ba17ac11 <55363fa0a04524d11efeaadee734d2db1756ed27; version=8a1fc8d698ac5e5916e3082a0f74450d71f9611f; version=d8cce4773c2b23d819baf5abedc62f7b430e8745

Published CVSS scores

5.5NIST NVDCVSS: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

CWE-476NULL Pointer Dereference

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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