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NVD / CVE Program· CNA Linux

CVE-2026-64530: net/sched: cls_api: Handle TC_ACT_CONSUMED in tcf_qevent_handle

Noroxi assessment

Priority: Monitor (action score 39/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.65% (FIRST EPSS); higher than 51.3% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: Linux Linux 2140c2f3f2e7b066e1ae616ede8856cafd8015e9, 447d493034a9cf7bf13a2abac86d0573d907ec2f, 5.15.212; azl3 kernel 6.6.144.1-1 on Azure Linux 3.0 6.6.145.2-1.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 2140c2f3f2e7b066e1ae616ede8856cafd8015e9, 447d493034a9cf7bf13a2abac86d0573d907ec2f, 5.15.212; azl3 kernel 6.6.144.1-1 on Azure Linux 3.0 6.6.145.2-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

CriticalCVSS 9.8 · v3.1—No exploit Fix available
Published
Jul 26, 2026
Updated
Nov 3, 2026
EPSS
0.6% · 51th percentile

Report tools

JSON

Action score

39

Monitor

Low priority for now.

CVSS
39 / 40 · 9.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.6%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · Linux
9.8
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • f5346df0591d10bc948761ca854b1fae6d2ef441, 6.8affected
    • 172ba7d46c202e679f3ccb10264c67416aaeb1c4 and later · before 5ed3d6f85991656667059d3fa5a1d683ac58c447affected · git
    • 0b5b831122fc3789fff75be433ba3e4dd7b779d4 and later · before f42e8134a3a1074b834a574d404352f867ba994aaffected · git
    • 73f7da5fd124f2cda9161e2e46114915e6e82e97 and later · before 447d493034a9cf7bf13a2abac86d0573d907ec2faffected · git
    • 3f14b377d01d8357eba032b4cabc8c1149b458b6 and later · before e1270e69dcf2c3512c453484178f2e9dc0db3f05affected · git
    • 3f14b377d01d8357eba032b4cabc8c1149b458b6 and later · before 2140c2f3f2e7b066e1ae616ede8856cafd8015e9affected · git
    • 3f14b377d01d8357eba032b4cabc8c1149b458b6 and later · before e28aedab9488343924d227b5a896faed67ce84d5affected · git
    • 3f14b377d01d8357eba032b4cabc8c1149b458b6 and later · before a8a02897f2b479127db261de05cbf0c28b98d159affected · git
    • 5.15.148 and later · before 5.15.212affected · semver
    • 6.1.75 and later · before 6.1.178affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
AlmaLinux:10kernelbefore 6.12.0-211.42.1.el10_26.12.0-211.42.1.el10_2
AlmaLinux:10kernel-64kbefore 6.12.0-211.42.1.el10_26.12.0-211.42.1.el10_2
AlmaLinux:10kernel-64k-corebefore 6.12.0-211.42.1.el10_26.12.0-211.42.1.el10_2
AlmaLinux:10kernel-64k-debugbefore 6.12.0-211.42.1.el10_26.12.0-211.42.1.el10_2
AlmaLinux:10kernel-64k-debug-corebefore 6.12.0-211.42.1.el10_26.12.0-211.42.1.el10_2
AlmaLinux:10kernel-64k-debug-develbefore 6.12.0-211.42.1.el10_26.12.0-211.42.1.el10_2
AlmaLinux:10kernel-64k-debug-devel-matchedbefore 6.12.0-211.42.1.el10_26.12.0-211.42.1.el10_2
AlmaLinux:10kernel-64k-debug-modulesbefore 6.12.0-211.42.1.el10_26.12.0-211.42.1.el10_2
AlmaLinux:10kernel-64k-debug-modules-corebefore 6.12.0-211.42.1.el10_26.12.0-211.42.1.el10_2
AlmaLinux:10kernel-64k-debug-modules-extrabefore 6.12.0-211.42.1.el10_26.12.0-211.42.1.el10_2
AlmaLinux:10kernel-64k-develbefore 6.12.0-211.42.1.el10_26.12.0-211.42.1.el10_2
AlmaLinux:10kernel-64k-devel-matchedbefore 6.12.0-211.42.1.el10_26.12.0-211.42.1.el10_2
AlmaLinux:10kernel-64k-modulesbefore 6.12.0-211.42.1.el10_26.12.0-211.42.1.el10_2
AlmaLinux:10kernel-64k-modules-corebefore 6.12.0-211.42.1.el10_26.12.0-211.42.1.el10_2
AlmaLinux:10kernel-64k-modules-extrabefore 6.12.0-211.42.1.el10_26.12.0-211.42.1.el10_2
AlmaLinux:10kernel-abi-stablelistsbefore 6.12.0-211.42.1.el10_26.12.0-211.42.1.el10_2
AlmaLinux:10kernel-corebefore 6.12.0-211.42.1.el10_26.12.0-211.42.1.el10_2
AlmaLinux:10kernel-cross-headersbefore 6.12.0-211.42.1.el10_26.12.0-211.42.1.el10_2
AlmaLinux:10kernel-debugbefore 6.12.0-211.42.1.el10_26.12.0-211.42.1.el10_2
AlmaLinux:10kernel-debug-corebefore 6.12.0-211.42.1.el10_26.12.0-211.42.1.el10_2
AlmaLinux:10kernel-debug-develbefore 6.12.0-211.42.1.el10_26.12.0-211.42.1.el10_2
AlmaLinux:10kernel-debug-devel-matchedbefore 6.12.0-211.42.1.el10_26.12.0-211.42.1.el10_2
AlmaLinux:10kernel-debug-modulesbefore 6.12.0-211.42.1.el10_26.12.0-211.42.1.el10_2
AlmaLinux:10kernel-debug-modules-corebefore 6.12.0-211.42.1.el10_26.12.0-211.42.1.el10_2

+96

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation
    40Plan
  • CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
    40Plan
  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-64529Jul 25, 2026 · crypto: qat - remove unused character device and IOCTLs
    31Monitor
  • ← EarlierCVE-2024-14040Jul 26, 2026 · net: nexthop: Increase weight to u16
    31Monitor
  • Later →CVE-2026-64531Jul 27, 2026 · net: openvswitch: reject oversized nested action attrs
    31Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux2140c2f3f2e7b066e1ae616ede8856cafd8015e9Vendor (CNA)
Linux Linux447d493034a9cf7bf13a2abac86d0573d907ec2fVendor (CNA)
Linux Linux5.15.212Vendor (CNA)
Linux Linux5ed3d6f85991656667059d3fa5a1d683ac58c447Vendor (CNA)
Linux Linux6.1.178Vendor (CNA)
Linux Linux6.6.145Vendor (CNA)
Linux Linux6.8Vendor (CNA)
Linux Linuxa8a02897f2b479127db261de05cbf0c28b98d159Vendor (CNA)
Linux Linuxe1270e69dcf2c3512c453484178f2e9dc0db3f05Vendor (CNA)
Linux Linuxe28aedab9488343924d227b5a896faed67ce84d5Vendor (CNA)
Linux Linuxf42e8134a3a1074b834a574d404352f867ba994aVendor (CNA)
azl3 kernel 6.6.144.1-1 on Azure Linux 3.06.6.145.2-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
almalinux:kernel5.14.0-687.33.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel6.12.0-211.42.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k5.14.0-687.33.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k6.12.0-211.42.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-core5.14.0-687.33.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-core6.12.0-211.42.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug5.14.0-687.33.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug6.12.0-211.42.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-core5.14.0-687.33.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-core6.12.0-211.42.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-devel5.14.0-687.33.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-devel6.12.0-211.42.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-devel-matched5.14.0-687.33.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-devel-matched6.12.0-211.42.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-modules5.14.0-687.33.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-modules6.12.0-211.42.1.el10_2 · AlmaLinux:10Package registry (OSV)
almalinux:kernel-64k-debug-modules-core5.14.0-687.33.1.el9_8 · AlmaLinux:9Package registry (OSV)
almalinux:kernel-64k-debug-modules-core6.12.0-211.42.1.el10_2 · AlmaLinux:10Package registry (OSV)

+34

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-645231 days apartnet/handshake: Take a long-lived file reference at submit
    39Monitor
  • CVE-2026-645411 days apartnet/smc: fix UAF in smc_cdc_rx_handler() by pinning the socket
    39Monitor
  • CVE-2026-639797 days apartnet/handshake: hand off the pinned file reference to accept_doit
    39Monitor
  • CVE-2026-645649 days apartsctp: don't free the ASCONF's own transport in DEL-IP processing
    39Monitor
  • CVE-2026-6811715 days aparttipc: clear sock->sk on the failed-insert path in tipc_sk_create()
    39Monitor
  • CVE-2026-6815615 days apartlibceph: refresh auth->authorizer_buf{,_len} after authorizer update
    39Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-416 · Use After Free

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

nvd-secondary

Root cause

After a memory region is freed, another reference pointing to it is still used. By then, the same region may have been allocated for different data.

The bug in code

The whole CWE-416 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

c
free(dev->buf);/* ... another thread is still running ... */process(dev->buf);

Fixed

c
lock(&dev->lock);free(dev->buf);dev->buf = NULL;unlock(&dev->lock);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. SSVC exploitation— → none
  2. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (6 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records