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VulnerabilityCVE-2026-64530Published 2026-07-26

CVE-2026-64530 — Linux

critical

As of 2026-07-27, CVE-2026-64530 is a CRITICAL-severity vulnerability in Linux, CVSS v3.1 9.8, EPSS 0.5% (40.4th percentile). No Threadlinqs-tracked threat campaign has been attributed to CVE-2026-64530 as of 2026-07-27; the identifier is re-checked against the Threadlinqs threat corpus on every daily ingest.

CVSS v3.1
9.8/10Critical
EPSS
0.5%Higher than 40.4% of scored CVEs
CISA KEV
NoNot in the KEV catalog
Tracked threats
0None linked yet
Priority
6.5/10Threadlinqs triage score
Published
Updated 2026-07-27
CVSS v3.1 9.8 (CRITICAL) · EPSS 0.5% (higher than 40.4% of all scored CVEs) · Priority 6.5/10 · Published 2026-07-26

Last updated:

What is CVE-2026-64530?

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.

Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction, and has high impact on confidentiality, integrity, availability. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 71 days ago.

Severity and exploitation probability

CVSS v3.1 base score
9.8 — CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS (FIRST)
0.5% probability of exploitation in the next 30 days, higher than 40.4% of all scored CVEs
CISA KEV
Not listed in the CISA Known Exploited Vulnerabilities catalog
Threadlinqs priority
6.5/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
Published
2026-07-26, last modified 2026-07-27

Is CVE-2026-64530 being exploited?

It currently carries a trending score of 40 in the Threadlinqs vulnerability feed.

Affected products and versions

How to fix CVE-2026-64530

No vendor patch reference has been recorded for CVE-2026-64530 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

Threat activity tracking CVE-2026-64530

No threat campaign in the Threadlinqs corpus currently references CVE-2026-64530, in its CVE list or as an indicator. The linkage is recomputed from the live corpus on every daily ingest, so this section fills in as soon as a tracked campaign cites the identifier.

Sources

Enriched from CVE.org, NVD, FIRST EPSS. Last verified by Threadlinqs on . This product uses the NVD API but is not endorsed or certified by the NVD.

Other references

Showing 5 of 7 recorded references.