← Back to the live CVE advisory feed

CVE-2026-64530: Linux

Severity

0 (N/A)

Vendor

LINUX

Affected versions

172ba7d46c202e679f3ccb10264c67416aaeb1c4 through before 5ed3d6f85991656667059d3fa5a1d683ac58c447; 0b5b831122fc3789fff75b

Patch status

Patched

Published

2026-07-26T07:16:41.680

Modified

2026-07-26T07:16:41.680

Why it matters

Vulnerability requiring standard triage and vendor validation.

Recommended admin actions

• Review during normal vulnerability triage unless the affected system is internet-facing or business-critical.
• Compare installed versions against the affected version range in the advisory.

Technical summary

In the Linux kernel, the following vulnerability has been resolved: net/sched: cls_api: Handle TC_ACT_CONSUMED in tcf_qevent_handle tcf_classify() can return TC_ACT_CONSUMED while the skb is held by the defragmentation engine (e.g. act_ct on out-of-order fragments). When that happens the skb is no longer owned by the caller and must not be touched again. tcf_qevent_handle() did not handle TC_ACT_CONSUMED: it fell through the switch and returned the skb to the caller as if classification had passed. The only qdisc that wires up qevents today is RED, via three call sites (qe_mark on RED_PROB_MARK/HARD_MARK, qe_early_drop on congestion_drop) red_enqueue() was continuing to operate on an skb it no longer owns in this case — enqueueing it, dropping it, or updating statistics. Resulting in a UAF. tc qdisc add dev eth0 root handle 1: red … qevent early_drop block 10 tc filter add block 10 … action ct (with ct defrag enabled and traffic that produces out-of-order fragments, e.g. a fragmented UDP stream) Handle TC_ACT_CONSUMED in tcf_qevent_handle() the same way the ingress and egress fast paths do: treat it as stolen and return NULL without touching the skb. Unlike the TC_ACT_STOLEN case, the skb must not be dropped/freed here, as it is no longer owned by us.

View the official NVD record for CVE-2026-64530

CVE data is sourced from NVD/CNA records and optional enrichment. Validate against the vendor advisory before taking production action.