4.8

CVE-2025-40022: crypto: af_alg - Fix incorrect boolean values in af_alg_ctx

Deferred
AliasesUBUNTU-CVE-2025-40022DEBIAN-CVE-2025-40022
Published 24-10-2025Last modified 15-10-2026

Vulnerability summary

CVE-2025-40022 is a medium (CVSS 4.8) vulnerability in linux. EPSS estimates a 0.24% chance of exploitation in the next 30 days, higher than 14.8% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 4.8, local access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
4.8/10
010
Medium · v4.0 (OSV · Ubuntu), selected by version preference
EPSS score
0.24%
0%100%
Low · +0.01 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 23 · Related 18
DLA-4379-1DLA-4404-1DSA-6053-1MGASA-2025-0309MGASA-2025-0310OPENSUSE-SU-2026:21555-1

Timeline

  1. 24-10-2025
    PublishedVulnerability first disclosed.
  2. 15-10-2026
    Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: crypto: af_alg - Fix incorrect boolean values in af_alg_ctx Commit 1b34cbbf4f01 ("crypto: af_alg - Disallow concurrent writes in af_alg_sendmsg") changed some fields from bool to 1-bit bitfields of type u32. However, some assignments to these fields, specifically 'more' and 'merge', assign values greater than 1. These relied on C's implicit conversion to bool, such that zero becomes false and nonzero becomes true. With a 1-bit bitfields of type u32 instead, mod 2 of the value is taken instead, resulting in 0 being assigned in some cases when 1 was intended. Fix this by restoring the bool type.

CVSS metrics

1 score · 1 source · 1 version

EPSS trend

Probability

0.24%

Chance of exploitation in the next 30 days

Percentile

15%

Versus all other CVEs

30-day change

Increase +0.01 pp

From 0.23% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

No weakness data has been published for this record.

Affected systems

Version check

Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Ubuntu87 products
  • linux< 6.17.0-6.6
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-aws< 6.17.0-1003.3
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Debian1 product
  • linux< 6.1.158-1 | < 6.12.57-1 | < 6.16.10-1
Linux1 product
  • linux≥ 0f28c4adbc4a97437874c9b669fd7958a8c6d6ce, < 3a21698ace915a445bce2d0dcfc84b6d2199baf7 | ≥ e4c1ec11132ec466f7362a95f36a506ce4dc08c9, < d382d6daf0184490f366562469a5673f65ee2662 | ≥ 1f323a48e9b5ebfe6dc7d130fdf5c3c0e92a07c8, < 54506c6335690f4ef1b9f154e34f5a604c72c1ed | ≥ 7c4491b5644e3a3708f3dbd7591be0a570135b84, < 8703940bd30b5ad94408d28d7192db2491cd3592 | ≥ 9aee87da5572b3a14075f501752e209801160d3d, < 316b090c2fee964c307a634fecc7df269664b158 | ≥ 45bcf60fe49b37daab1acee57b27211ad1574042, < fbe96bd25423e61273d8831e995260b429d850b6 | ≥ 1b34cbbf4f011a121ef7b2d7d6e6920a036d5285, < d0ca0df179c4b21e2a6c4a4fb637aa8fa14575cb | ≥ 6.1.154, < 6.1.155 | ≥ 6.6.108, < 6.6.109 | ≥ 6.12.49, < 6.12.50 | ≥ 6.16.9, < 6.16.10

3 vendors · 89 products

References

14 links
Show all 14 references