CVE-2026-45860

netfilter: nf_conncount: increase the connection clean up limit to 64

State: Published
Severity: 7.5 High
Published: May 27, 2026
Updated: Oct 19, 2026
Reserved: May 13, 2026

Description

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

Scores

CVSS	Score	Vector	Source
3.1	7.5 High	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H	Linux

Weaknesses

CWE-400 Uncontrolled Resource Consumption

Affected Products

Product	Versions
LinuxLinux	f106694733c66a48740c25bc4e212e9b2ea364ce to before a5c9e14e0e8923218ae881d5e78c990c07694966Affected be69850b461e7b491d87a22e33ab76fdd04b725e to before 13eede458fdf231f1bf96a398feea4ad1553f14cAffected d265929930e2ffafc744c0ae05fb70acd53be1ee to before fa85432d58c8e74b39333edbf8d28df2985dfc79Affected d265929930e2ffafc744c0ae05fb70acd53be1ee to before 0792ad077d776c2dcf20f0484e2461ded1b77a24Affected d265929930e2ffafc744c0ae05fb70acd53be1ee to before 3d0994ed0aa1fc0a2c5e620b765e8defdd021bffAffected d265929930e2ffafc744c0ae05fb70acd53be1ee to before 6e5fa7add3e76da068a478d905be64be8fa4e80aAffected d265929930e2ffafc744c0ae05fb70acd53be1ee to before 0af0812baf2d363176c9b76fc07e33f13aede8dbAffected d265929930e2ffafc744c0ae05fb70acd53be1ee to before 21d033e472735ecec677f1ae46d6740b5e47a4f3Affected 5.10.248 to before 5.10.252Affected 5.15.198 to before 5.15.202Affected
LinuxLinux	5.19Affected before 5.19Not affected 5.10.252 through 5.10.Not affected 5.15.202 through 5.15.Not affected 6.1.165 through 6.1.Not affected 6.6.128 through 6.6.Not affected 6.12.75 through 6.12.Not affected 6.18.14 through 6.18.Not affected 6.19.4 through 6.19.*Not affected 7.0 and laterNot affected

Product

Versions

LinuxLinux

f106694733c66a48740c25bc4e212e9b2ea364ce to before a5c9e14e0e8923218ae881d5e78c990c07694966Affected
be69850b461e7b491d87a22e33ab76fdd04b725e to before 13eede458fdf231f1bf96a398feea4ad1553f14cAffected
d265929930e2ffafc744c0ae05fb70acd53be1ee to before fa85432d58c8e74b39333edbf8d28df2985dfc79Affected
d265929930e2ffafc744c0ae05fb70acd53be1ee to before 0792ad077d776c2dcf20f0484e2461ded1b77a24Affected
d265929930e2ffafc744c0ae05fb70acd53be1ee to before 3d0994ed0aa1fc0a2c5e620b765e8defdd021bffAffected
d265929930e2ffafc744c0ae05fb70acd53be1ee to before 6e5fa7add3e76da068a478d905be64be8fa4e80aAffected
d265929930e2ffafc744c0ae05fb70acd53be1ee to before 0af0812baf2d363176c9b76fc07e33f13aede8dbAffected
d265929930e2ffafc744c0ae05fb70acd53be1ee to before 21d033e472735ecec677f1ae46d6740b5e47a4f3Affected
5.10.248 to before 5.10.252Affected
5.15.198 to before 5.15.202Affected

LinuxLinux

5.19Affected
before 5.19Not affected
5.10.252 through 5.10.*Not affected
5.15.202 through 5.15.*Not affected
6.1.165 through 6.1.*Not affected
6.6.128 through 6.6.*Not affected
6.12.75 through 6.12.*Not affected
6.18.14 through 6.18.*Not affected
6.19.4 through 6.19.*Not affected
7.0 and laterNot affected

References

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