CVE-2025-38517

System crash via nonexistent semaphore acquisition

Published Aug 16, 2025 · Updated May 11, 2026

Null-pointer dereference in Linux kernel lib/alloc_tag allows local users to crash the system during a memory-allocation failure. alloc_tag_top_users() acquires alloc_tag_cttype->mod_lock without first rejecting a NULL or error-valued alloc_tag_cttype pointer. The path is reachable when allocation tagging is uninitialized or fails initialization, or when memory profiling is compiled but disabled at boot; reported impact is a system crash.

CVSS severity5.5
Medium
EPSS probability0.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Null-pointer dereference in Linux kernel lib/alloc_tag allows local users to crash the system during a memory-allocation failure. alloc_tag_top_users() acquires alloc_tag_cttype->mod_lock without first rejecting a NULL or error-valued alloc_tag_cttype pointer. The path is reachable when allocation tagging is uninitialized or fails initialization, or when memory profiling is compiled but disabled at boot; reported impact is a system crash.

The record

CVE
CVE-2025-38517
Published
Aug 16, 2025
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 16, 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

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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=1438d349d16b78d88f9e978a4a5496f078c8191b <22bf79c0c2301b6e15a688220284b147774d277e
  2. Affected versionversion=1438d349d16b78d88f9e978a4a5496f078c8191b <99af22cd34688cc0d535a1919e0bea4cbc6c1ea1
  3. Affected versionversion=1438d349d16b78d88f9e978a4a5496f078c8191b <febc0b5dbabda414565bdfaaaa59d26f787d5fe7
  4. Affected versionversion=6.10

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=1438d349d16b78d88f9e978a4a5496f078c8191b <22bf79c0c2301b6e15a688220284b147774d277e; version=1438d349d16b78d88f9e978a4a5496f078c8191b <99af22cd34688cc0d535a1919e0bea4cbc6c1ea1; version=1438d349d16b78d88f9e978a4a5496f078c8191b <febc0b5dbabda414565bdfaaaa59d26f787d5fe7; version=6.10

Published CVSS scores

5.5CanonicalCVSS: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

T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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