7.8

CVE-2025-39931: crypto: af_alg - Set merge to zero early in af_alg_sendmsg

Modified
AliasesUBUNTU-CVE-2025-39931DEBIAN-CVE-2025-39931
Published 04-10-2025Last modified 15-10-2026

Vulnerability summary

CVE-2025-39931 is a high (CVSS 7.8) Use of Uninitialized Resource vulnerability in linux. EPSS estimates a 0.17% chance of exploitation in the next 30 days, higher than 6.3% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 7.8, local access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
7.8/10
010
High · v3.1 (CVE.org)
EPSS score
0.17%
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 36 · Related 32
DLA-4379-1DSA-6053-1MGASA-2025-0309MGASA-2025-0310OPENSUSE-SU-2025:20081-1SUSE-SU-2025:21040-1

Timeline

  1. 04-10-2025
    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 - Set merge to zero early in af_alg_sendmsg If an error causes af_alg_sendmsg to abort, ctx->merge may contain a garbage value from the previous loop. This may then trigger a crash on the next entry into af_alg_sendmsg when it attempts to do a merge that can't be done. Fix this by setting ctx->merge to zero near the start of the loop.

CVSS metrics

5 scores · 4 sources · 2 versions

EPSS trend

Probability

0.17%

Chance of exploitation in the next 30 days

Percentile

6%

Versus all other CVEs

30-day change

Increase +0.01 pp

From 0.16% 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

Affected systems

Version check

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

Ubuntu149 products
  • linuxAll versions (No fix recorded) | < 5.15.0-198.208 | < 6.8.0-106.106
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-awsAll versions (No fix recorded) | < 5.15.0-1117.124 | < 6.8.0-1050.53
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Linux2 products
  • linux≥ 8ff590903d5fc7f5a0a988c38267a3d08e6393a2, < 28f6f37abca7c5c9eb3959c66310f1d4d98b8aaf | ≥ 8ff590903d5fc7f5a0a988c38267a3d08e6393a2, < db2b42425dfbde4983b0c20fb7cfa05f70e6a745 | ≥ 8ff590903d5fc7f5a0a988c38267a3d08e6393a2, < 6241b9e2809b12da9130894cf5beddf088dc1b8a | ≥ 8ff590903d5fc7f5a0a988c38267a3d08e6393a2, < 2374c11189ef704a3e4863646369f1b8e6a27d71 | ≥ 8ff590903d5fc7f5a0a988c38267a3d08e6393a2, < 24c1106504c625fabd3b7229611af617b4c27ac7 | ≥ 8ff590903d5fc7f5a0a988c38267a3d08e6393a2, < 045ee26aa3920a47ec46d7fcb302420bf01fd753 | ≥ 8ff590903d5fc7f5a0a988c38267a3d08e6393a2, < 9574b2330dbd2b5459b74d3b5e9619d39299fc6f | 2.6.38
  • linux_kernel≥ 2.6.38, < 6.1.154 | ≥ 6.2, < 6.6.108 | ≥ 6.7, < 6.12.49 | ≥ 6.13, < 6.16.9 | 6.17:rc1 | 6.17:rc2 | 6.17:rc3 | 6.17:rc4 | 6.17:rc5 | 6.17:rc6
Debian1 product
  • linux< 6.1.158-1 | < 6.12.57-1 | < 6.16.9-1

3 vendors · 152 products

References

31 links
Show all 31 references