Time-of-check Time-of-use (TOCTOU) Affecting kernel-rt-kvm package, versions *
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-CENTOS10-KERNELRTKVM-18921742
- published19 Aug 2026
- disclosed15 Aug 2026
Introduced: 15 Aug 2026
NewCVE-2026-72418 (opens in a new tab)How to fix?
There is no fixed version for Centos:10 kernel-rt-kvm.
NVD Description
Note: Versions mentioned in the description apply only to the upstream kernel-rt-kvm package and not the kernel-rt-kvm package as distributed by Centos.
See How to fix? for Centos:10 relevant fixed versions and status.
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.
References
- https://bugzilla.redhat.com/show_bug.cgi?id=2516428
- https://access.redhat.com/security/cve/CVE-2026-72418
- https://git.kernel.org/stable/c/000ac6830b56499d6b65fd91486ce6689eb02be4
- https://git.kernel.org/stable/c/329f2626ee5cb8fafdf6b58b624311529c57cb45
- https://git.kernel.org/stable/c/3793d24de224943e0a6016bbeffb6f5c4cea2e3d
- https://git.kernel.org/stable/c/abef7f817217fcb62c11821d6b895063eadb2828
- https://git.kernel.org/stable/c/be52572c6d55f677ba76869d3c63805c0d4891a3
- https://git.kernel.org/stable/c/c8b6f36f766991e3ebebec6596daee4b04dcbc49
- https://git.kernel.org/stable/c/cbe2d14a7c5b1fc71821fbfee5c4963917411e92
- https://git.kernel.org/stable/c/ebfe8249ba79e4ff0f1e3aad8787b992ef27f026