5.5

CVE-2025-21636: sctp: sysctl: plpmtud_probe_interval: avoid using current->nsproxy

Modified
AliasesUBUNTU-CVE-2025-21636DEBIAN-CVE-2025-21636
Published 19-01-2025Last modified 11-05-2026

Vulnerability summary

CVE-2025-21636 is a medium (CVSS 5.5) NULL Pointer Dereference vulnerability in linux. EPSS estimates a 0.22% chance of exploitation in the next 30 days, higher than 12.3% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 5.5, local access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
5.5/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.22%
0%100%
Low · 0.00 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 37 · Related 35
DLA-4076-1DSA-5860-1MGASA-2025-0030MGASA-2025-0032SUSE-SU-2025:0784-1SUSE-SU-2025:0847-1

Timeline

  1. 19-01-2025
    PublishedVulnerability first disclosed.
  2. 11-05-2026
    Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: sctp: sysctl: plpmtud_probe_interval: 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.probe_interval' is used.

CVSS metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.22%

Chance of exploitation in the next 30 days

Percentile

12%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.22% 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.

Ubuntu123 products
  • linux< 5.15.0-135.146 | < 6.8.0-60.63
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-aws< 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≥ d1e462a7a5f359cbb9a0e8fbfafcfb6657034105, < 1dc5da6c4178f3e4b95c631418f72de9f86c0449 | ≥ d1e462a7a5f359cbb9a0e8fbfafcfb6657034105, < 44ee8635922b6eb940faddb961a8347c6857d722 | ≥ d1e462a7a5f359cbb9a0e8fbfafcfb6657034105, < 284a221f8fa503628432c7bb5108277c688c6ffa | ≥ d1e462a7a5f359cbb9a0e8fbfafcfb6657034105, < bcf8c60074e81ed2ac2d35130917175a3949c917 | ≥ d1e462a7a5f359cbb9a0e8fbfafcfb6657034105, < 6259d2484d0ceff42245d1f09cc8cb6ee72d847a | 5.14
  • linux_kernel≥ 5.14, < 5.15.177 | ≥ 5.16, < 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 · 126 products

References

38 links
Show all 38 references