CVE-2023-53728

Unbounded timer-ID search via lockless race

Published Oct 22, 2025 · Updated Oct 22, 2025

Race condition in POSIX timers in affected Linux kernel releases allows local users to force an unbounded timer-ID search during concurrent allocation. The posix_timer_add() path reads sig->posix_timer_id before taking hash_lock, so concurrent allocation can capture -1 as the loop's unreachable stop value. Triggering the defect requires a race at signed-ID wraparound after exhausting a huge ID space; the published record describes an endless loop as unlikely and reports no broader impact.

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

What happened

Race condition in POSIX timers in affected Linux kernel releases allows local users to force an unbounded timer-ID search during concurrent allocation. The posix_timer_add() path reads sig->posix_timer_id before taking hash_lock, so concurrent allocation can capture -1 as the loop's unreachable stop value. Triggering the defect requires a race at signed-ID wraparound after exhausting a huge ID space; the published record describes an endless loop as unlikely and reports no broader impact.

The record

CVE
CVE-2023-53728
Published
Oct 22, 2025
Updated
Oct 22, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. Oct 22, 2025CVE publishedPublication date reported by the CVE source.
  2. Oct 22, 2025Record 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=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <322377cc909defcca9451487484845e7e1d20d1b
  2. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <37175e25edf7cc0d5a2cd2c2a1cbe2dcbf4a1937
  3. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <6a0ac84501b4fec73a1a823c55cf13584c43f418
  4. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <8ad6679a5bb97cdb3e14942729292b4bfcc0e223
  5. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <8ce8849dd1e78dadcee0ec9acbd259d239b7069f
  6. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <8dc52c200b889bc1cb34288fbf623d4ff381d2ae
  7. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <9ea26a8494a0a9337e7415eafd6f3ed940327dc5
  8. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <ef535e0315afd098c4beb1da364847eca4b56a20

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <322377cc909defcca9451487484845e7e1d20d1b; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <37175e25edf7cc0d5a2cd2c2a1cbe2dcbf4a1937; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <6a0ac84501b4fec73a1a823c55cf13584c43f418; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <8ad6679a5bb97cdb3e14942729292b4bfcc0e223; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <8ce8849dd1e78dadcee0ec9acbd259d239b7069f; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <8dc52c200b889bc1cb34288fbf623d4ff381d2ae; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <9ea26a8494a0a9337e7415eafd6f3ed940327dc5; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <ef535e0315afd098c4beb1da364847eca4b56a20

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.

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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
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

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Your stack

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