CVE-2025-21648: netfilter: conntrack: clamp maximum hashtable size to INT_MAX
First published: Sun Jan 19 2025(Updated: )
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.
Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Linux Kernel | ||
| debian/linux | <=5.10.223-1 | 5.10.234-1 6.1.129-1 6.1.133-1 6.12.21-1 6.12.22-1 |
| debian/linux-6.1 | 6.1.129-1~deb11u1 |
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Reference Links
- https://git.kernel.org/stable/c/a965f7f0ea3ae61b9165bed619d5d6da02c75f80
- https://git.kernel.org/stable/c/b1b2353d768f1b80cd7fe045a70adee576b9b338
- https://git.kernel.org/stable/c/5552b4fd44be3393b930434a7845d8d95a2a3c33
- https://git.kernel.org/stable/c/d5807dd1328bbc86e059c5de80d1bbee9d58ca3d
- https://git.kernel.org/stable/c/f559357d035877b9d0dcd273e0ff83e18e1d46aa
- https://git.kernel.org/stable/c/b541ba7d1f5a5b7b3e2e22dc9e40e18a7d6dbc13
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2025-21648
- https://nvd.nist.gov/vuln/detail/CVE-2025-21648
- https://launchpad.net/bugs/cve/CVE-2025-21648
- https://security-tracker.debian.org/tracker/CVE-2025-21648
- https://ubuntu.com/security/CVE-2025-21648
- https://git.kernel.org/linus/b541ba7d1f5a5b7b3e2e22dc9e40e18a7d6dbc13
Frequently Asked Questions
What is the severity of CVE-2025-21648?
The severity of CVE-2025-21648 is classified as moderate.
How do I fix CVE-2025-21648?
To fix CVE-2025-21648, update your Linux kernel to the latest stable version that contains the patch addressing this vulnerability.
Who is affected by CVE-2025-21648?
CVE-2025-21648 affects users of the Linux kernel who utilize the conntrack module.
What impact does CVE-2025-21648 have on systems?
CVE-2025-21648 can lead to potential memory allocation warnings and degrade system stability during hash table resizing.
Is CVE-2025-21648 exploitable remotely?
CVE-2025-21648 is not directly exploitable remotely but may affect systems processing network traffic that rely on conntrack.
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