CVE-2026-43499Public exploit

Local privilege escalation via incorrect waiter task

Published May 21, 2026 · Updated May 21, 2026

Use-after-free in the Linux Kernel rtmutex subsystem allows local users to gain root privileges via crafted priority-inheritance futex operations. During proxy-lock rollback, remove_waiter() uses the current task instead of waiter::task, leaving pi_blocked_on dangling and altering the waiter tree without the required task lock. Any unprivileged local account can invoke the futex path without user interaction; successful exploitation grants root access, while failure can panic the kernel.

CVSS severity7.8
High
EPSS probability0.79%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in the Linux Kernel rtmutex subsystem allows local users to gain root privileges via crafted priority-inheritance futex operations. During proxy-lock rollback, remove_waiter() uses the current task instead of waiter::task, leaving pi_blocked_on dangling and altering the waiter tree without the required task lock. Any unprivileged local account can invoke the futex path without user interaction; successful exploitation grants root access, while failure can panic the kernel.

The record

CVE
CVE-2026-43499
Published
May 21, 2026
Updated
May 21, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-416, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 21, 2026CVE publishedPublication date reported by the CVE source.
  2. May 21, 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=2.6.39
  2. Affected versionversion=8161239a8bcce9ad6b537c04a1fa3b5c68bae693 <3bfdc63936dd4773109b7b8c280c0f3b5ae7d349
  3. Affected versionversion=8161239a8bcce9ad6b537c04a1fa3b5c68bae693 <3fb7394a837740770f0d6b4b30567e60786a63f2
  4. Affected versionversion=8161239a8bcce9ad6b537c04a1fa3b5c68bae693 <6d52dfcb2a5db86e346cf51f8fcf2071b8085166
  5. Affected versionversion=8161239a8bcce9ad6b537c04a1fa3b5c68bae693 <88614876370aac8ad1050ad785a4c095ba17ac11
  6. Affected versionversion=8161239a8bcce9ad6b537c04a1fa3b5c68bae693 <8a1fc8d698ac5e5916e3082a0f74450d71f9611f

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=2.6.39; version=8161239a8bcce9ad6b537c04a1fa3b5c68bae693 <3bfdc63936dd4773109b7b8c280c0f3b5ae7d349; version=8161239a8bcce9ad6b537c04a1fa3b5c68bae693 <3fb7394a837740770f0d6b4b30567e60786a63f2; version=8161239a8bcce9ad6b537c04a1fa3b5c68bae693 <6d52dfcb2a5db86e346cf51f8fcf2071b8085166; version=8161239a8bcce9ad6b537c04a1fa3b5c68bae693 <88614876370aac8ad1050ad785a4c095ba17ac11; version=8161239a8bcce9ad6b537c04a1fa3b5c68bae693 <8a1fc8d698ac5e5916e3082a0f74450d71f9611f

Published CVSS scores

7.8LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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 exploitPublished

Weakness, pattern, technique

CWE-416Use After Free
T1068Exploitation for Privilege Escalation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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