CVE-2025-39912

Kernel crash via out-of-order credential release

Published Oct 1, 2025 · Updated May 11, 2026

Denial of service in Linux kernel 6.12 through 6.16.7 and 6.17-rc1 through 6.17-rc5 allows local users to trigger a crash. The NFS LOCALIO completion path releases pageio data before restoring overridden credentials, allowing an immediate nfsd_file release to put f_cred while it remains current and trip the __put_cred BUG_ON. A co-located NFS client and server using AUTH_SYS must exercise LOCALIO; the BUG can panic or reboot hosts configured to panic on BUG.

CVSS severity5.5
Medium
EPSS probability0.14%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Linux kernel 6.12 through 6.16.7 and 6.17-rc1 through 6.17-rc5 allows local users to trigger a crash. The NFS LOCALIO completion path releases pageio data before restoring overridden credentials, allowing an immediate nfsd_file release to put f_cred while it remains current and trip the __put_cred BUG_ON. A co-located NFS client and server using AUTH_SYS must exercise LOCALIO; the BUG can panic or reboot hosts configured to panic on BUG.

The record

CVE
CVE-2025-39912
Published
Oct 1, 2025
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 1, 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=6.12
  2. Affected versionversion=b9f5dd57f4a52990963eeb1f1b58d00f717ece69 <57c1bb02b4fc8eec6eb01736e7fad26dffacf18c
  3. Affected versionversion=b9f5dd57f4a52990963eeb1f1b58d00f717ece69 <992203a1fba51b025c60ec0c8b0d9223343dea95
  4. Affected versionversion=b9f5dd57f4a52990963eeb1f1b58d00f717ece69 <c250be1d75bf80dc5ab46f0b434b746c1868a1ea

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=6.12; version=b9f5dd57f4a52990963eeb1f1b58d00f717ece69 <57c1bb02b4fc8eec6eb01736e7fad26dffacf18c; version=b9f5dd57f4a52990963eeb1f1b58d00f717ece69 <992203a1fba51b025c60ec0c8b0d9223343dea95; version=b9f5dd57f4a52990963eeb1f1b58d00f717ece69 <c250be1d75bf80dc5ab46f0b434b746c1868a1ea

Published CVSS scores

5.5NIST NVDCVSS: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.

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Application or System Exploitation

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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