CVE-2025-21648
netfilter: conntrack: clamp maximum hashtable size to INT_MAX
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.
INFO
Published Date :
Jan. 19, 2025, 11:15 a.m.
Last Modified :
Nov. 3, 2025, 9:19 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Update the Linux kernel to the latest stable version.
- Apply the specific patch for netfilter: conntrack.
- Reboot the system after applying updates.
- Verify the kernel version and conntrack configuration.
Public PoC/Exploit Available at Github
CVE-2025-21648 has a 1 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2025-21648.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2025-21648 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2025-21648
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
None
Java Shell
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2025-21648 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2025-21648 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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CVE Modified by af854a3a-2127-422b-91ae-364da2661108
Nov. 03, 2025
Action Type Old Value New Value Added Reference https://lists.debian.org/debian-lts-announce/2025/03/msg00001.html Added Reference https://lists.debian.org/debian-lts-announce/2025/03/msg00002.html -
Initial Analysis by [email protected]
Oct. 16, 2025
Action Type Old Value New Value Added CVSS V3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Added CWE NVD-CWE-Other Added CPE Configuration OR *cpe:2.3:o:linux:linux_kernel:6.13:rc2:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:6.13:rc1:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:6.13:rc3:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:6.13:rc4:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:6.13:rc5:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:6.13:rc6:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 4.7.1 up to (excluding) 5.10.234 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.11 up to (excluding) 5.15.177 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.16 up to (excluding) 6.1.125 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.2 up to (excluding) 6.6.72 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.7 up to (excluding) 6.12.10 *cpe:2.3:o:linux:linux_kernel:4.7:-:*:*:*:*:*:* Added Reference Type kernel.org: https://git.kernel.org/stable/c/5552b4fd44be3393b930434a7845d8d95a2a3c33 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/a965f7f0ea3ae61b9165bed619d5d6da02c75f80 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/b1b2353d768f1b80cd7fe045a70adee576b9b338 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/b541ba7d1f5a5b7b3e2e22dc9e40e18a7d6dbc13 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/d5807dd1328bbc86e059c5de80d1bbee9d58ca3d Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/f559357d035877b9d0dcd273e0ff83e18e1d46aa Types: Patch -
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Feb. 02, 2025
Action Type Old Value New Value Added Reference https://git.kernel.org/stable/c/a965f7f0ea3ae61b9165bed619d5d6da02c75f80 -
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Jan. 23, 2025
Action Type Old Value New Value Added Reference https://git.kernel.org/stable/c/b1b2353d768f1b80cd7fe045a70adee576b9b338 -
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Jan. 19, 2025
Action Type Old Value New Value Added 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. Added Reference https://git.kernel.org/stable/c/5552b4fd44be3393b930434a7845d8d95a2a3c33 Added Reference https://git.kernel.org/stable/c/b541ba7d1f5a5b7b3e2e22dc9e40e18a7d6dbc13 Added Reference https://git.kernel.org/stable/c/d5807dd1328bbc86e059c5de80d1bbee9d58ca3d Added Reference https://git.kernel.org/stable/c/f559357d035877b9d0dcd273e0ff83e18e1d46aa