CVE-2023-53815

Kernel livelock via timer deletion retry loop

Published Dec 9, 2025 · Updated May 11, 2026

Concurrency flaw in affected Linux kernel releases allows local users to trigger a livelock during concurrent POSIX timer deletion. The itimer_delete() retry loop unlocks and immediately retries while an expired timer callback is running, allowing the deleting task to preempt the delivery task that must complete the callback. The condition requires an RT kernel or a POSIX CPU timer using task-work delivery, and the affected task can remain unable to make progress.

CVSS severityUnavailable
Unscored
EPSS probability0.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Concurrency flaw in affected Linux kernel releases allows local users to trigger a livelock during concurrent POSIX timer deletion. The itimer_delete() retry loop unlocks and immediately retries while an expired timer callback is running, allowing the deleting task to preempt the delivery task that must complete the callback. The condition requires an RT kernel or a POSIX CPU timer using task-work delivery, and the affected task can remain unable to make progress.

The record

CVE
CVE-2023-53815
Published
Dec 9, 2025
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. Dec 9, 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

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=5.4
  2. Affected versionversion=ec8f954a40da8cd3d159713b608e901f0cd909a9 <0670c4c567b27bd8f999a943028f4fe60d1a1106
  3. Affected versionversion=ec8f954a40da8cd3d159713b608e901f0cd909a9 <9d9e522010eb5685d8b53e8a24320653d9d4cbbf
  4. Affected versionversion=ec8f954a40da8cd3d159713b608e901f0cd909a9 <c1968bb8a28625cc95d2ad3ca872ab98c9c36d59
  5. Affected versionversion=ec8f954a40da8cd3d159713b608e901f0cd909a9 <e7aff15ba29ba4b3052786b1636fa5c4aa39e179
  6. Affected versionversion=ec8f954a40da8cd3d159713b608e901f0cd909a9 <f1be1ed32daa053484222f7f9beb2b16c624dffd
  7. Affected versionversion=ec8f954a40da8cd3d159713b608e901f0cd909a9 <f9bd298e3e4d3fd6e19f017789a42d0f332cd555

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=5.4; version=ec8f954a40da8cd3d159713b608e901f0cd909a9 <0670c4c567b27bd8f999a943028f4fe60d1a1106; version=ec8f954a40da8cd3d159713b608e901f0cd909a9 <9d9e522010eb5685d8b53e8a24320653d9d4cbbf; version=ec8f954a40da8cd3d159713b608e901f0cd909a9 <c1968bb8a28625cc95d2ad3ca872ab98c9c36d59; version=ec8f954a40da8cd3d159713b608e901f0cd909a9 <e7aff15ba29ba4b3052786b1636fa5c4aa39e179; version=ec8f954a40da8cd3d159713b608e901f0cd909a9 <f1be1ed32daa053484222f7f9beb2b16c624dffd; version=ec8f954a40da8cd3d159713b608e901f0cd909a9 <f9bd298e3e4d3fd6e19f017789a42d0f332cd555

Published CVSS scores

No CVSS assessment is available in this record.

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499Endpoint Denial of Service

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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo