CVE-2025-21648: Linux Kernel

Medium severity, CVSS 5.5. EPSS: 0.2% chance of exploitation in the next 30 days.

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 Kernel: from 4.7.1, before 5.10.234 (fixed in 5.10.234); from 5.11, before 5.15.177 (fixed in 5.15.177); from 5.16, before 6.1.125 (fixed in 6.1.125); from 6.2, before 6.6.72 (fixed in 6.6.72); from 6.7, before 6.12.10 (fixed in 6.12.10); version 4.7 only; …

Published 2025-01-19. Last modified 2026-07-14.