7.1

CVE-2025-21637: sctp: sysctl: udp_port: avoid using current->nsproxy

Modified
AliasesUBUNTU-CVE-2025-21637DEBIAN-CVE-2025-21637
Published 19-01-2025Last modified 05-08-2026

Vulnerability summary

CVE-2025-21637 is a high (CVSS 7.1) NULL Pointer Dereference vulnerability in linux. EPSS estimates a 0.21% chance of exploitation in the next 30 days, higher than 11.7% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 7.1, local access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
7.1/10
010
High · v3.1 (CVE.org)
EPSS score
0.21%
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. 05-08-2026
    Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: sctp: sysctl: udp_port: 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, but that would increase the size of this fix, while 'sctp.ctl_sock' still needs to be retrieved from 'net' structure.

CVSS metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.21%

Chance of exploitation in the next 30 days

Percentile

12%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.21% 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≥ 046c052b475e7119b6a30e3483e2888fc606a2f8, < 0a0966312ac3eedd7f5f2a766ed4702df39a9a65 | ≥ 046c052b475e7119b6a30e3483e2888fc606a2f8, < e919197fb8616331f5dc81e4c3cc3d12769cb725 | ≥ 046c052b475e7119b6a30e3483e2888fc606a2f8, < 55627918febdf9d71107a1e68d1528dc591c9a15 | ≥ 046c052b475e7119b6a30e3483e2888fc606a2f8, < 5b77d73f3be5102720fb685b9e6900e3500e1096 | ≥ 046c052b475e7119b6a30e3483e2888fc606a2f8, < c10377bbc1972d858eaf0ab366a311b39f8ef1b6 | 5.11
  • linux_kernel≥ 5.11, < 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
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