CVE-2026-45873: netfilter: nft_set_rbtree: check for partial overlaps in anonymous sets

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-05-27 · updated 2026-06-25

Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: nft_set_rbtree: check for partial overlaps in anonymous sets Userspace provides an optimized representation in case intervals are adjacent, where the end element is omitted. The existing partial overlap detection logic skips anonymous set checks on start elements for this reason. However, it is possible to add intervals that overlap to this anonymous where two start elements with the same, eg. A-B, A-C where C < B. start end A B start end A C Restore the check on overlapping start elements to report an overlap.

Affected products

Linux kernel: from 4.19.316 before 4.20; from 5.4.262 before 5.5; from 5.10.166 before 5.10.252; from 5.15.91 before 5.15.202; from 6.1.9 before 6.1.165; from 6.2.1 before 6.6.128 — fixed in 4.20, 5.10.252, 5.15.202, 5.5, 6.1.165, 6.12.75

How to fix

Upgrade to a fixed version: Linux kernel 4.20, 5.10.252, 5.15.202, 5.5. Check the vendor advisory for mitigations.

References

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