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CVE.org (no NVD analysis yet)· CNA Linux

CVE-2026-99167: net/sched: fix use-after-free in __tcf_action_put()

Noroxi assessment

Priority: Monitor (action score 31/100)

  • 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: 0.13% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 2465d27ef90de9105c2bffb6c35f8ce08918e642, 2e012e431aa271ef3c84206f48854f539c03bff0, 4d83a3fc03bc595dd39b79ad61288738fbb1f2ba; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 Release Notes; azl3 kernel 6.6.159.1-1 on Azure Linux 3.0 Release Notes.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 2465d27ef90de9105c2bffb6c35f8ce08918e642, 2e012e431aa271ef3c84206f48854f539c03bff0, 4d83a3fc03bc595dd39b79ad61288738fbb1f2ba; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 Release Notes; azl3 kernel 6.6.159.1-1 on Azure Linux 3.0 Release Notes 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: fix use-after-free in __tcf_action_put() __tcf_action_put() decrements the reference count before decrementing the binding count. Another thread can free the action between these operations, causing the binding-count update to access freed memory. KASAN reports it as: BUG: KASAN: slab-use-after-free in __tcf_action_put+0x327/0x340 Write of size 4 at addr ff11000000d46420 by task tc-put-pause/64 Hold the action IDR mutex across both counter updates and IDR removal, keeping cleanup outside the lock.

HighCVSS 7.8 · v3.1—No exploit Fix available
Published
Oct 28, 2026
Updated
Oct 31, 2026
EPSS
0.1% · 2th percentile
CWE
—

Report tools

JSON

Action score

31

Monitor

Low priority for now.

CVSS
31 / 40 · 7.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CNA vs NVD score

NVD
—
CNA · Linux
7.8
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.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-99167

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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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

    • 4.19affected
    • 16af6067392c40e454e49eec834843ab03643d96 and later · before 4d83a3fc03bc595dd39b79ad61288738fbb1f2baaffected · git
    • 16af6067392c40e454e49eec834843ab03643d96 and later · before fd01abed2568209f7daaf60e5ee68ae4a4744f48affected · git
    • 16af6067392c40e454e49eec834843ab03643d96 and later · before fcc7d734ceccfab8ec3398c5b34f8e775d459507affected · git
    • 16af6067392c40e454e49eec834843ab03643d96 and later · before fde33eb9955d819af282d5f5e84684eaec248291affected · git
    • 16af6067392c40e454e49eec834843ab03643d96 and later · before 969ad6f2b266f383b44194d50d15631969b26222affected · git
    • 16af6067392c40e454e49eec834843ab03643d96 and later · before 2465d27ef90de9105c2bffb6c35f8ce08918e642affected · git
    • 16af6067392c40e454e49eec834843ab03643d96 and later · before 2e012e431aa271ef3c84206f48854f539c03bff0affected · git
    • 16af6067392c40e454e49eec834843ab03643d96 and later · before 7b16eb911091aae237a8673da94e4dfb9cd21d54affected · git
    • before 4.19not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxfrom 0—
Debian:13linuxbefore 6.12.115-26.12.115-2

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-2026-99165Oct 28, 2026 · sctp: revalidate output stream after association connect wait
    0Monitor
  • ← EarlierCVE-2026-99166Oct 28, 2026 · net: rds: fix uninitialized trans dereference in CM event handler
    0Monitor
  • Later →CVE-2026-99168Oct 28, 2026 · mshv_vtl: Check per-CPU register page before mmap
    0Monitor

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 Linux2465d27ef90de9105c2bffb6c35f8ce08918e642Vendor (CNA)
Linux Linux2e012e431aa271ef3c84206f48854f539c03bff0Vendor (CNA)
Linux Linux4d83a3fc03bc595dd39b79ad61288738fbb1f2baVendor (CNA)
Linux Linux7b16eb911091aae237a8673da94e4dfb9cd21d54Vendor (CNA)
Linux Linux969ad6f2b266f383b44194d50d15631969b26222Vendor (CNA)
Linux Linuxfcc7d734ceccfab8ec3398c5b34f8e775d459507Vendor (CNA)
Linux Linuxfd01abed2568209f7daaf60e5ee68ae4a4744f48Vendor (CNA)
Linux Linuxfde33eb9955d819af282d5f5e84684eaec248291Vendor (CNA)
azl3 kernel 6.6.157.1-1 on Azure Linux 3.0Release NotesMicrosoft (MSRC)
azl3 kernel 6.6.159.1-1 on Azure Linux 3.0Release NotesMicrosoft (MSRC)
debian:linux6.12.115-2 · Debian:13Package registry (OSV)

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.

  1. Published
  2. Fix recordedsame day
  3. TodayNov 4, 2026+7 d
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.

No nightly-computed relations.

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

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • 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
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

—

CVSS vector

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

nvd-secondary

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. CVSS— → 7.8
  2. Severity— → high
  3. Exploit maturity— → none
  4. Fix✗ → ✓

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

References

Show all references (7 more)

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

All records