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Review reviewCritical

CVE-2026-64530

Linux

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_...

CVSS
9.8
EPSS
-
- percentile
CISA KEV
Not listed
Published
2026.07.26
PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability-
Technical severityCVSS 9.8

Vulnerability overview

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_...

Affected product and versions

Product
Linux
Affected versions
>= 172ba7d46c202e679f3ccb10264c67416aaeb1c4 < 5ed3d6f85991656667059d3fa5a1d683ac58c447, >= 0b5b831122fc3789fff75be433ba3e4dd7b779d4 < f42e8134a3a1074b834a574d404352f867ba994a, >= 73f7da5fd124f2cda9161e2e46114915e6e82e97 < 447d493034a9cf7bf13a2abac86d0573d907ec2f, >= 3f14b377d01d8357eba032b4cabc8c1149b458b6 < e1270e69dcf2c3512c453484178f2e9dc0db3f05, >= 3f14b377d01d8357eba032b4cabc8c1149b458b6 < 2140c2f3f2e7b066e1ae616ede8856cafd8015e9, >= 3f14b377d01d8357eba032b4cabc8c1149b458b6 < e28aedab9488343924d227b5a896faed67ce84d5, >= 3f14b377d01d8357eba032b4cabc8c1149b458b6 < a8a02897f2b479127db261de05cbf0c28b98d159, >= f5346df0591d10bc948761ca854b1fae6d2ef441, >= 5.15.148 < 5.15.212, >= 6.1.75 < 6.1.178, >= 6.6.14 < 6.6.145, >= 6.7.2 < 6.8, >= 6.8
Fixed versions
No verified fixed-version field is available yet

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
  1. 1
    Identify

    Confirm that Linux and an affected version are present.

  2. 2
    Prioritize

    Combine exploitation signals with asset exposure and business criticality.

  3. 3
    Remediate

    Follow the vendor advisory or supported update path and preserve rollback options.

  4. 4
    Verify

    Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CWE
Not available
CVE-2026-64530 — Linux | SECUFOCUS NOW