CVE-2026-46331: net/sched: fix pedit partial COW leading to page cache corruption

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-06-16 · updated 2026-10-15
Weakness: CWE-190

Description

In the Linux kernel, the following vulnerability has been resolved: net/sched: fix pedit partial COW leading to page cache corruption tcf_pedit_act() computes the COW range for skb_ensure_writable() once before the key loop using tcfp_off_max_hint, but the hint does not account for the runtime header offset added by typed keys. This can leave part of the write region un-COW'd. Fix by moving skb_ensure_writable() inside the per-key loop where the actual write offset is known, and add overflow checking on the offset arithmetic. For negative offsets (e.g. Ethernet header edits at ingress), use skb_cow() to COW the headroom instead. Guard offset_valid() against INT_MIN, where negation is undefined.

Affected products

Linux kernel: from 4.19.244 before 4.20; from 5.4.195 before 5.5; from 5.10.117 before 5.11; from 5.15.41 before 5.16; from 5.17.9 before 5.18; from 5.18.1 before 6.12.94 — fixed in 4.20, 5.11, 5.16, 5.18, 5.5, 6.12.94

How to fix

Upgrade to a fixed version: Linux kernel 4.20, 5.11, 5.16, 5.18. Check the vendor advisory for mitigations.

References

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