5.5

CVE-2025-21639: linux NULL Pointer Dereference

CVSS: 5.5v3.1MediumModified
AliasesUBUNTU-CVE-2025-21639DEBIAN-CVE-2025-21639
Published 19-01-2025Last modified 15-10-2026
Open JSON

Vulnerability summary

CVE-2025-21639 is a medium (CVSS 5.5) NULL Pointer Dereference vulnerability in linux. EPSS estimates a 0.23% chance of exploitation in the next 30 days, higher than 12.8% of scored vulnerabilities.

Overall risk
22/100
0100
Low · default modelHow is this calculated?
CVSS score
5.5/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.23%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 50 · Related 47
DLA-4075-1DLA-4076-1DSA-5860-1MGASA-2025-0030MGASA-2025-0032SUSE-SU-2025:0784-1

Timeline

  1. 19-01-2025
    PublishedVulnerability first disclosed.
  2. 15-10-2026
    Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: sctp: sysctl: rto_min/max: avoid using current->nsproxy As mentioned in a previous commit of this series, using the 'net' structure via 'current' is not recommended for different reasons: - Inconsistency: getting info from the reader's/writer's netns vs only from the opener's netns. - current->nsproxy can be NULL in some cases, resulting in an 'Oops' (null-ptr-deref), e.g. when the current task is exiting, as spotted by syzbot [1] using acct(2). The 'net' structure can be obtained from the table->data using container_of(). Note that table->data could also be used directly, as this is the only member needed from the 'net' structure, but that would increase the size of this fix, to use '*data' everywhere 'net->sctp.rto_min/max' is used.

CVSS metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.23%

Chance of exploitation in the next 30 days

Percentile

13%

Versus all other CVEs

30-day change

0.00 pp

From 0.23% on 21-09-2026

21-09-202621-10-2026
EPSS score
0.23%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Ubuntu135 products
  • linuxAll versions (No fix recorded) | < 5.4.0-211.231 | < 5.15.0-135.146 | < 6.8.0-60.63
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-awsAll versions (No fix recorded) | < 5.4.0-1142.152 | < 5.15.0-1080.87 | < 6.8.0-1029.31
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Linux2 products
  • linux≥ 4f3fdf3bc59cafd14c3bc2c2369efad34c7aa8b5, < c8d179f3b1c1d60bf4484f50aa67b4c70f91bff9 | ≥ 4f3fdf3bc59cafd14c3bc2c2369efad34c7aa8b5, < 246428bfb9e7db15c5cd08e1d0eca41b65af2b06 | ≥ 4f3fdf3bc59cafd14c3bc2c2369efad34c7aa8b5, < 0f78f09466744589e420935e646ae78212a38290 | ≥ 4f3fdf3bc59cafd14c3bc2c2369efad34c7aa8b5, < 4059507e34aa5fe0fa9fd5b2b5f0c8b26ab2d482 | ≥ 4f3fdf3bc59cafd14c3bc2c2369efad34c7aa8b5, < dc9d0e3cfd16f66fbf0862857c6b391c8613ca9f | ≥ 4f3fdf3bc59cafd14c3bc2c2369efad34c7aa8b5, < c87f1f6ade56c711f8736901e330685b453e420e | ≥ 4f3fdf3bc59cafd14c3bc2c2369efad34c7aa8b5, < 9fc17b76fc70763780aa78b38fcf4742384044a5 | 3.13
  • linux_kernel≥ 3.13, < 6.1.125 | ≥ 6.2, < 6.6.72 | ≥ 6.7, < 6.12.10 | 6.13:rc1 | 6.13:rc2 | 6.13:rc3 | 6.13:rc4 | 6.13:rc5 | 6.13:rc6
Debian1 product
  • linux< 6.1.128-1 | < 6.12.10-1

3 vendors · 138 products

References

53 links
Show all 53 references