CVE-2026-31555

Local denial of service via stale futex pointer

Published Apr 24, 2026 · Updated Apr 24, 2026

Stale-pointer handling in the Linux kernel futex PI path allows local users to interrupt service by racing an exiting futex owner. After wait_for_owner_exiting consumes the referenced task, futex_lock_pi leaves exiting uncleared and can pass that stale pointer back after a retry returns a different error. The race requires concurrent PI futex operations and owner exit; the documented result is a kernel warning and availability loss, with no reported data disclosure or modification.

CVSS severity5.5
Medium
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stale-pointer handling in the Linux kernel futex PI path allows local users to interrupt service by racing an exiting futex owner. After wait_for_owner_exiting consumes the referenced task, futex_lock_pi leaves exiting uncleared and can pass that stale pointer back after a retry returns a different error. The race requires concurrent PI futex operations and owner exit; the documented result is a kernel warning and availability loss, with no reported data disclosure or modification.

The record

CVE
CVE-2026-31555
Published
Apr 24, 2026
Updated
Apr 24, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 24, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 24, 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=3ef240eaff36b8119ac9e2ea17cbf41179c930ba <210d36d892de5195e6766c45519dfb1e65f3eb83
  2. Affected versionversion=3ef240eaff36b8119ac9e2ea17cbf41179c930ba <33095ae3bdde5e5c264d7e88a2f3e7703a26c7aa
  3. Affected versionversion=3ef240eaff36b8119ac9e2ea17cbf41179c930ba <5e8e06bf8909e79b4acd950cf578cfc2f10bbefa
  4. Affected versionversion=3ef240eaff36b8119ac9e2ea17cbf41179c930ba <71112e62807d1925dc3ae6188b11f8cfc85aec23
  5. Affected versionversion=3ef240eaff36b8119ac9e2ea17cbf41179c930ba <7475dfad10a05a5bfadebf5f2499bd61b19ed293
  6. Affected versionversion=3ef240eaff36b8119ac9e2ea17cbf41179c930ba <92e47ad03e03dbb5515bdf06444bf6b1e147310d
  7. Affected versionversion=3ef240eaff36b8119ac9e2ea17cbf41179c930ba <de7c0c04ad868f2cee6671b11c0a6d20421af1da
  8. Affected versionversion=3ef240eaff36b8119ac9e2ea17cbf41179c930ba <e7824ec168d2ac883a213cd1f4d6cc0816002a85
  9. Affected versionversion=5.5
  10. Affected versionversion=61fa9f167caaa73d0a7c88f498eceeb12c6fa3db
  11. Affected versionversion=7874eee0130adf9bee28e8720bb5dd051089def3
  12. Affected versionversion=cf16e42709aa86aa3e37f3acc3d13d5715d90096
  13. Affected versionversion=f2a9957e5c08b1b1caacd18a3dc4c0a1bdb7b463
  14. Affected versionversion=fc3b55ef2c840bb2746b2d8121a0788de84f7fac

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=3ef240eaff36b8119ac9e2ea17cbf41179c930ba <210d36d892de5195e6766c45519dfb1e65f3eb83; version=3ef240eaff36b8119ac9e2ea17cbf41179c930ba <33095ae3bdde5e5c264d7e88a2f3e7703a26c7aa; version=3ef240eaff36b8119ac9e2ea17cbf41179c930ba <5e8e06bf8909e79b4acd950cf578cfc2f10bbefa; version=3ef240eaff36b8119ac9e2ea17cbf41179c930ba <71112e62807d1925dc3ae6188b11f8cfc85aec23; version=3ef240eaff36b8119ac9e2ea17cbf41179c930ba <7475dfad10a05a5bfadebf5f2499bd61b19ed293; version=3ef240eaff36b8119ac9e2ea17cbf41179c930ba <92e47ad03e03dbb5515bdf06444bf6b1e147310d; version=3ef240eaff36b8119ac9e2ea17cbf41179c930ba <de7c0c04ad868f2cee6671b11c0a6d20421af1da; version=3ef240eaff36b8119ac9e2ea17cbf41179c930ba <e7824ec168d2ac883a213cd1f4d6cc0816002a85; version=5.5; version=61fa9f167caaa73d0a7c88f498eceeb12c6fa3db; version=7874eee0130adf9bee28e8720bb5dd051089def3; version=cf16e42709aa86aa3e37f3acc3d13d5715d90096; version=f2a9957e5c08b1b1caacd18a3dc4c0a1bdb7b463; version=fc3b55ef2c840bb2746b2d8121a0788de84f7fac

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

T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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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