CVE-2025-40348

Kernel crash via slab object-extension allocation race

Published Dec 16, 2025 · Updated Dec 16, 2025

Race condition in Linux kernel 6.12.54 through 6.12.55 and 6.17.4 through 6.17.5 allows local users to crash the kernel. In mm/slub.c, competing alloc_slab_obj_exts() calls can let a failed allocation overwrite another thread's valid slab->obj_exts pointer with OBJEXTS_ALLOC_FAIL, leading the losing thread to dereference NULL. Exploitation requires low-privileged local access and winning a high-complexity race; the grounded consequence is a kernel crash and service interruption.

CVSS severity7.0
High
EPSS probability0.20%
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 Linux kernel 6.12.54 through 6.12.55 and 6.17.4 through 6.17.5 allows local users to crash the kernel. In mm/slub.c, competing alloc_slab_obj_exts() calls can let a failed allocation overwrite another thread's valid slab->obj_exts pointer with OBJEXTS_ALLOC_FAIL, leading the losing thread to dereference NULL. Exploitation requires low-privileged local access and winning a high-complexity race; the grounded consequence is a kernel crash and service interruption.

The record

CVE
CVE-2025-40348
Published
Dec 16, 2025
Updated
Dec 16, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 16, 2025CVE publishedPublication date reported by the CVE source.
  2. Dec 16, 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=07e38a54cabd9b4de7ceb7f075f29ffa463e458a <7c34feda6a9a203c9744281f1b6671b7dad2012d
  2. Affected versionversion=6.12.54 <6.12.56
  3. Affected versionversion=6.17.4 <6.17.6
  4. Affected versionversion=715b6a5b41dae39baeaa40d3386b548bb278b9c2 <c7af5300d78460fc5037ddc77113ba3dbfe77dc0
  5. Affected versionversion=f7381b9116407ba2a429977c80ff8df953ea9354 <6ed8bfd24ce1cb31742b09a3eb557cd008533eec

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=07e38a54cabd9b4de7ceb7f075f29ffa463e458a <7c34feda6a9a203c9744281f1b6671b7dad2012d; version=6.12.54 <6.12.56; version=6.17.4 <6.17.6; version=715b6a5b41dae39baeaa40d3386b548bb278b9c2 <c7af5300d78460fc5037ddc77113ba3dbfe77dc0; version=f7381b9116407ba2a429977c80ff8df953ea9354 <6ed8bfd24ce1cb31742b09a3eb557cd008533eec

Published CVSS scores

7.0OracleCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/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.

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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