5.5

CVE-2025-21648: netfilter: conntrack: clamp maximum hashtable size to INT_MAX

Modified
AliasesUBUNTU-CVE-2025-21648DEBIAN-CVE-2025-21648
Published 19-01-2025Last modified 15-10-2026

Vulnerability summary

CVE-2025-21648 is a medium (CVSS 5.5) vulnerability in linux. EPSS estimates a 0.22% chance of exploitation in the next 30 days, higher than 12.4% 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 (NVD)
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 44 · Related 39
DLA-4075-1DLA-4076-1DSA-5860-1MGASA-2025-0030MGASA-2025-0032RHSA-2025:20518

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: netfilter: conntrack: clamp maximum hashtable size to INT_MAX Use INT_MAX as maximum size for the conntrack hashtable. Otherwise, it is possible to hit WARN_ON_ONCE in __kvmalloc_node_noprof() when resizing hashtable because __GFP_NOWARN is unset. See: 0708a0afe291 ("mm: Consider __GFP_NOWARN flag for oversized kvmalloc() calls") Note: hashtable resize is only possible from init_netns.

CVSS metrics

3 scores · 3 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

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.

Ubuntu134 products
  • linuxAll versions (No fix recorded) | < 5.15.0-135.146 | < 6.8.0-60.63
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-awsAll versions (No fix recorded) | < 5.15.0-1080.87 | < 6.8.0-1029.31
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Linux2 products
  • linux≥ 9cc1c73ad66610bffc80b691136ffc1e9a3b1a58, < a965f7f0ea3ae61b9165bed619d5d6da02c75f80 | ≥ 9cc1c73ad66610bffc80b691136ffc1e9a3b1a58, < b1b2353d768f1b80cd7fe045a70adee576b9b338 | ≥ 9cc1c73ad66610bffc80b691136ffc1e9a3b1a58, < 5552b4fd44be3393b930434a7845d8d95a2a3c33 | ≥ 9cc1c73ad66610bffc80b691136ffc1e9a3b1a58, < d5807dd1328bbc86e059c5de80d1bbee9d58ca3d | ≥ 9cc1c73ad66610bffc80b691136ffc1e9a3b1a58, < f559357d035877b9d0dcd273e0ff83e18e1d46aa | ≥ 9cc1c73ad66610bffc80b691136ffc1e9a3b1a58, < b541ba7d1f5a5b7b3e2e22dc9e40e18a7d6dbc13 | 4.7
  • linux_kernel≥ 4.7.1, < 5.10.234 | ≥ 5.11, < 5.15.177 | ≥ 5.16, < 6.1.125 | ≥ 6.2, < 6.6.72 | ≥ 6.7, < 6.12.10 | 4.7 | 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 · 137 products

References

42 links
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