CVE-2026-45860: netfilter: nf_conncount: increase the connection clean up limit to 64
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
Metrics
- CVSS v3.1
- 7.5
- Severity
- HIGH
- Fixed in
- 0
- Affected Products
- 2
Fix available
- Linux / Linux< a5c9e14e0e8923218ae881d5e78c990c07694966 (from f106694733c66a48740c25bc4e212e9b2ea364ce) · < 13eede458fdf231f1bf96a398feea4ad1553f14c (from be69850b461e7b491d87a22e33ab76fdd04b725e) · < fa85432d58c8e74b39333edbf8d28df2985dfc79 (from d265929930e2ffafc744c0ae05fb70acd53be1ee) · < 0792ad077d776c2dcf20f0484e2461ded1b77a24 (from d265929930e2ffafc744c0ae05fb70acd53be1ee) · < 3d0994ed0aa1fc0a2c5e620b765e8defdd021bff (from d265929930e2ffafc744c0ae05fb70acd53be1ee) · < 6e5fa7add3e76da068a478d905be64be8fa4e80a (from d265929930e2ffafc744c0ae05fb70acd53be1ee)
- Linux / Linux5.19Fixed in 0, 5.10.252, 5.15.202, 6.1.165, 6.6.128, 6.12.75, 6.18.14, 6.19.4, 7.0
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H