Copyright © 2012 Red Hat, Inc. All rights reserved. Moderate 2026-05-27T00:00:00 kernel: netfilter: nf_conncount: increase the connection clean up limit to 64 7.0 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H CWE-770

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conncount: increase the connection clean up limit to 64 After the optimization to only perform one GC per jiffy, a new problem was introduced. If more than 8 new connections are tracked per jiffy the list won't be cleaned up fast enough possibly reaching the limit wrongly. In order to prevent this issue, only skip the GC if it was already triggered during the same jiffy and the increment is lower than the clean up limit. In addition, increase the clean up limit to 64 connections to avoid triggering GC too often and do more effective GCs. This has been tested using a HTTP server and several performance tools while having nft_connlimit/xt_connlimit or OVS limit configured. Output of slowhttptest + OVS limit at 52000 connections: slow HTTP test status on 340th second: initializing: 0 pending: 432 connected: 51998 error: 0 closed: 0 service available: YES

A flaw was found in the Linux kernel's netfilter connection counting (nf_conncount) feature. This vulnerability occurs when the system tracks more than eight new connections per jiffy, causing the connection list to not be cleaned up efficiently. A remote attacker could exploit this by rapidly establishing connections, leading the system to incorrectly believe it has reached its connection limit. This can result in a denial of service, preventing legitimate users from establishing new connections.

Red Hat Enterprise Linux 10 Affected kernel Red Hat Enterprise Linux 6 Not affected kernel Red Hat Enterprise Linux 7 Not affected kernel Red Hat Enterprise Linux 7 Not affected kernel-rt Red Hat Enterprise Linux 8 Not affected kernel Red Hat Enterprise Linux 8 Not affected kernel-rt Red Hat Enterprise Linux 9 Not affected kernel Red Hat Enterprise Linux 9 Not affected kernel-rt https://www.cve.org/CVERecord?id=CVE-2026-45860 https://nvd.nist.gov/vuln/detail/CVE-2026-45860 https://lore.kernel.org/linux-cve-announce/2026052710-CVE-2026-45860-d52c@gregkh/T