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National Vulnerability Database

National Vulnerability Database

NVD

National Vulnerability Database
  1. Vulnerabilities

CVE-2026-72418 Detail

Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conncount: prevent connlimit drops for early confirmed ct Commit 69894e5b4c5e ("netfilter: nft_connlimit: update the count if add was skipped") introduced a regression where packets for valid connections are dropped when using connlimit for soft-limiting scenarios. The issue occurs when a new connection reuses a socket currently in the TIME_WAIT state. In this scenario, the connection tracking entry is evaluated as already confirmed. Previously, __nf_conncount_add() assumed that if a connection was confirmed and did not originate from the loopback interface, it should skip the addition and return -EEXIST. Skipping the addition triggers a garbage collection run that cleans up the TIME_WAIT connection. Consequently, the active connection count drops to 0, which xt_connlimit mishandles, leading to the false rejection of the perfectly valid new connection. Fix this by replacing the interface check with protocol-agnostic state checks. We now skip the tree insertion and preserve the lockless garbage collection optimization only if the connection is IPS_ASSURED. This allows early-confirmed setup packets (such as reused TIME_WAIT sockets or locally generated SYN-ACKs) to be properly evaluated and counted without falsely dropping. The goto check_connections path is maintained to ensure these setup packets are deduplicated correctly. This has been tested with slowhttptest and HTTP server configured locally to ensure we are not breaking soft-limiting scenarios for local or external connections. In addition, it was tested with a OVS zone limit too.


Metrics

 
NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

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URL Source(s) Tag(s)
https://git.kernel.org/stable/c/000ac6830b56499d6b65fd91486ce6689eb02be4 kernel.org
https://git.kernel.org/stable/c/329f2626ee5cb8fafdf6b58b624311529c57cb45 kernel.org
https://git.kernel.org/stable/c/3793d24de224943e0a6016bbeffb6f5c4cea2e3d kernel.org
https://git.kernel.org/stable/c/abef7f817217fcb62c11821d6b895063eadb2828 kernel.org
https://git.kernel.org/stable/c/be52572c6d55f677ba76869d3c63805c0d4891a3 kernel.org
https://git.kernel.org/stable/c/c8b6f36f766991e3ebebec6596daee4b04dcbc49 kernel.org
https://git.kernel.org/stable/c/cbe2d14a7c5b1fc71821fbfee5c4963917411e92 kernel.org
https://git.kernel.org/stable/c/ebfe8249ba79e4ff0f1e3aad8787b992ef27f026 kernel.org

Weakness Enumeration

CWE-ID CWE Name Source

Change History

1 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2026-72418
NVD Published Date:
08/15/2026
NVD Last Modified:
08/15/2026
Source:
kernel.org