Linux Kernel up to 6.4.6 posix_timer_add allocation of resources

CVSS Meta Temp Score
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CTI Interest Score
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5.3$0-$5k0.00

Summaryinfo

A vulnerability identified as critical has been detected in Linux Kernel up to 6.4.6. Impacted is the function posix_timer_add. The manipulation leads to allocation of resources. This vulnerability is referenced as CVE-2023-53728. No exploit is available. You should upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.4.6. It has been rated as critical. This issue affects the function posix_timer_add. The manipulation with an unknown input leads to a allocation of resources vulnerability. Using CWE to declare the problem leads to CWE-770. The product allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor. The impact remains unknown. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: posix-timers: Ensure timer ID search-loop limit is valid posix_timer_add() tries to allocate a posix timer ID by starting from the cached ID which was stored by the last successful allocation. This is done in a loop searching the ID space for a free slot one by one. The loop has to terminate when the search wrapped around to the starting point. But that's racy vs. establishing the starting point. That is read out lockless, which leads to the following problem: CPU0 CPU1 posix_timer_add() start = sig->posix_timer_id; lock(hash_lock); ... posix_timer_add() if (++sig->posix_timer_id < 0) start = sig->posix_timer_id; sig->posix_timer_id = 0; So CPU1 can observe a negative start value, i.e. -1, and the loop break never happens because the condition can never be true: if (sig->posix_timer_id == start) break; While this is unlikely to ever turn into an endless loop as the ID space is huge (INT_MAX), the racy read of the start value caught the attention of KCSAN and Dmitry unearthed that incorrectness. Rewrite it so that all id operations are under the hash lock.

The advisory is shared at git.kernel.org. The identification of this vulnerability is CVE-2023-53728 since 10/22/2025. Technical details are known, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 284771 (EulerOS 2.0 SP10 : kernel (EulerOS-SA-2026-1050)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 4.14.322, 4.19.291, 5.4.251, 5.10.188, 5.15.150, 6.1.107 or 6.4.7 eliminates this vulnerability. Applying the patch 8dc52c200b889bc1cb34288fbf623d4ff381d2ae/9ea26a8494a0a9337e7415eafd6f3ed940327dc5/8ad6679a5bb97cdb3e14942729292b4bfcc0e223/322377cc909defcca9451487484845e7e1d20d1b/ef535e0315afd098c4beb1da364847eca4b56a20/6a0ac84501b4fec73a1a823c55cf13584c43f418/37175e25edf7cc0d5a2cd2c2a1cbe2dcbf4a1937/8ce8849dd1e78dadcee0ec9acbd259d239b7069f is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (284771) and CERT Bund (WID-SEC-2025-2394). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Affected

  • Red Hat Enterprise Linux
  • SUSE Linux
  • Oracle Linux
  • Open Source Linux Kernel
  • Dell NetWorker

Productinfo

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Version

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Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.5
VulDB Meta Temp Score: 5.3

VulDB Base Score: 5.5
VulDB Temp Score: 5.3
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Allocation of resources
CWE: CWE-770 / CWE-400 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 284771
Nessus Name: EulerOS 2.0 SP10 : kernel (EulerOS-SA-2026-1050)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 4.14.322/4.19.291/5.4.251/5.10.188/5.15.150/6.1.107/6.4.7
Patch: 8dc52c200b889bc1cb34288fbf623d4ff381d2ae/9ea26a8494a0a9337e7415eafd6f3ed940327dc5/8ad6679a5bb97cdb3e14942729292b4bfcc0e223/322377cc909defcca9451487484845e7e1d20d1b/ef535e0315afd098c4beb1da364847eca4b56a20/6a0ac84501b4fec73a1a823c55cf13584c43f418/37175e25edf7cc0d5a2cd2c2a1cbe2dcbf4a1937/8ce8849dd1e78dadcee0ec9acbd259d239b7069f

Timelineinfo

10/22/2025 Advisory disclosed
10/22/2025 +0 days CVE reserved
10/22/2025 +0 days VulDB entry created
02/28/2026 +129 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2023-53728 (🔒)
GCVE (CVE): GCVE-0-2023-53728
GCVE (VulDB): GCVE-100-329345
CERT Bund: WID-SEC-2025-2394 - Linux Kernel: Mehrere Schwachstellen

Entryinfo

Created: 10/22/2025 16:37
Updated: 02/28/2026 13:15
Changes: 10/22/2025 16:37 (58), 01/02/2026 09:35 (7), 01/16/2026 05:45 (2), 02/28/2026 13:15 (1)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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