CVE-2025-37808Public exploit

Kernel availability loss via softirq-unsafe null cipher mutex

Published May 8, 2025 · Updated May 11, 2026

Improper locking in the Linux kernel allows local users to disrupt kernel availability through AF_ALG cryptographic sockets. crypto/crypto_null.c protects the default null skcipher with a mutex even though AF_ALG can free it in softirq context, where sleeping locks are invalid. Low-privileged local access reaches the faulty path; public records do not specify whether the resulting interruption is a hang, crash, or reboot.

CVSS severity5.5
Medium
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper locking in the Linux kernel allows local users to disrupt kernel availability through AF_ALG cryptographic sockets. crypto/crypto_null.c protects the default null skcipher with a mutex even though AF_ALG can free it in softirq context, where sleeping locks are invalid. Low-privileged local access reaches the faulty path; public records do not specify whether the resulting interruption is a hang, crash, or reboot.

The record

CVE
CVE-2025-37808
Published
May 8, 2025
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 8, 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=330234638e16b7b95e8e5e6be719a61a93f074b8 <0486de3c1b8223138dcc614846bd76364f758de6
  2. Affected versionversion=330234638e16b7b95e8e5e6be719a61a93f074b8 <1b66a5920b7fc7cc6251192a3fcad115b6d75dd5
  3. Affected versionversion=330234638e16b7b95e8e5e6be719a61a93f074b8 <1dd4a8561d85dea545cf93f56efc48df8176e218
  4. Affected versionversion=330234638e16b7b95e8e5e6be719a61a93f074b8 <8cf2945512a8c0ef74ddd5b5a4f6b6a2fb1a4efb
  5. Affected versionversion=330234638e16b7b95e8e5e6be719a61a93f074b8 <dcc47a028c24e793ce6d6efebfef1a1e92f80297
  6. Affected versionversion=330234638e16b7b95e8e5e6be719a61a93f074b8 <e27244cbe10658a66b8775be7f0acc4ad2f618d6
  7. Affected versionversion=330234638e16b7b95e8e5e6be719a61a93f074b8 <e307c54ac8198bf09652c72603ba6e6d97798410
  8. Affected versionversion=330234638e16b7b95e8e5e6be719a61a93f074b8 <f7a5a5c8e1ec16a4b2041398abe95de0e14572ef
  9. Affected versionversion=4.2

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=330234638e16b7b95e8e5e6be719a61a93f074b8 <0486de3c1b8223138dcc614846bd76364f758de6; version=330234638e16b7b95e8e5e6be719a61a93f074b8 <1b66a5920b7fc7cc6251192a3fcad115b6d75dd5; version=330234638e16b7b95e8e5e6be719a61a93f074b8 <1dd4a8561d85dea545cf93f56efc48df8176e218; version=330234638e16b7b95e8e5e6be719a61a93f074b8 <8cf2945512a8c0ef74ddd5b5a4f6b6a2fb1a4efb; version=330234638e16b7b95e8e5e6be719a61a93f074b8 <dcc47a028c24e793ce6d6efebfef1a1e92f80297; version=330234638e16b7b95e8e5e6be719a61a93f074b8 <e27244cbe10658a66b8775be7f0acc4ad2f618d6; version=330234638e16b7b95e8e5e6be719a61a93f074b8 <e307c54ac8198bf09652c72603ba6e6d97798410; version=330234638e16b7b95e8e5e6be719a61a93f074b8 <f7a5a5c8e1ec16a4b2041398abe95de0e14572ef; version=4.2

Published CVSS scores

4.4Oracle LinuxCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
6.8SUSECVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5SUSECVSS: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 exploitPublished

Weakness, pattern, technique

T1499Endpoint Denial of Service

Public exploit references

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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