# CVE-2025-21648

## Summary

- **CVE ID:** CVE-2025-21648
- **Severity:** MEDIUM
- **CVSS Score:** 5.5 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)
- **CWE:** N/A
- **Published:** Jan 19, 2025
- **Last Modified:** Sep 8, 2026

## 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.

## Affected Products

- Linux — Linux (9cc1c73ad66610bffc80b691136ffc1e9a3b1a58)
- Linux — Linux (4.7)
- Linux — Linux (0)
- Linux — Linux (5.10.234)
- Linux — Linux (5.15.177)
- Linux — Linux (6.1.125)
- Linux — Linux (6.6.72)
- Linux — Linux (6.12.10)
- Linux — Linux (6.13)

## References

- [CNA](https://git.kernel.org/stable/c/a965f7f0ea3ae61b9165bed619d5d6da02c75f80)
- [CNA](https://git.kernel.org/stable/c/b1b2353d768f1b80cd7fe045a70adee576b9b338)
- [CNA](https://git.kernel.org/stable/c/5552b4fd44be3393b930434a7845d8d95a2a3c33)
- [CNA](https://git.kernel.org/stable/c/d5807dd1328bbc86e059c5de80d1bbee9d58ca3d)
- [CNA](https://git.kernel.org/stable/c/f559357d035877b9d0dcd273e0ff83e18e1d46aa)
- [CNA](https://git.kernel.org/stable/c/b541ba7d1f5a5b7b3e2e22dc9e40e18a7d6dbc13)
- [CVE](https://lists.debian.org/debian-lts-announce/2025/03/msg00001.html)
- [CVE](https://lists.debian.org/debian-lts-announce/2025/03/msg00002.html)
- [siemens-SADP](https://cert-portal.siemens.com/productcert/html/ssa-265688.html)
- [siemens-SADP](https://cert-portal.siemens.com/productcert/html/ssa-019113.html)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.22%
- **EPSS Percentile:** 12.5

---
_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-18._