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

CVE-2026-98289: af_unix: Unify scc_index when finalising SCC in __unix_walk_scc().

Noroxi assessment

Priority: Monitor (action score 0/100)

  • 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: 0.16% (FIRST EPSS).
  • Fixed version: Linux Linux 4a4263dfeabad72f95e8ab6e15146861fa4144dd, 6.2, 6.7; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 6.6.159.1-1.

Low priority for now. Upgrade to Linux Linux 4a4263dfeabad72f95e8ab6e15146861fa4144dd, 6.2, 6.7; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 6.6.159.1-1 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: af_unix: Unify scc_index when finalising SCC in __unix_walk_scc(). Commit bfdb01283ee8 ("af_unix: Assign a unique index to SCC.") changed Tarjan's algorithm to update lowlink with lowlink, which is called lowpoint (unix_vertex.scc_index). unix_vertex_dead() assumes all vertices in an SCC share the same lowpoint, but this is not always true if an SCC has two or more back edges, depending on the order of DFS. For example, the graph below has two back edges from B to A and from C to B. A --> B --> C ^ | ^ | `----' `----' If DFS walks through A -> B -> C -> B (-> C -> B) -> A (-> B -> A), each index and scc_index will be updated as follows. A --> B --> C C = (3, 3) (index, scc_index) B = (2, 2) A = (1, 1) A ... B ... C C = (3, 2)<-. ^ | B = (2, 2) -' `----' A = (1, 1) A ... B ... C C = (3, 2) ^ | . . B = (2, 1)<-. `----' .... A = (1, 1) -' Then, unix_vertex_dead() thinks that B is passed to another SCC with scc_index 2, and the SCC is not garbage-collected. This does not happen if DFS walks in a different order below or starts from B. 1 3 A --> B --> C ^ | ^ | `----' `----' 2 4 Let's unify scc_index across the SCC when finalising it. Note that updating v->index was previously done in unix_scc_dead(), when called from __unix_walk_scc(), just to save one loop. Since __unix_walk_scc() now iterates over the SCC anyway, the update is moved back to __unix_walk_scc() and 'fast' argument is dropped.

—No exploit Fix available
Published
Oct 6, 2026
Updated
Oct 19, 2026
EPSS
0.1% · 5th percentile
CWE
—

Report tools

JSON

Action score

0

Monitor

Low priority for now.

CVSS
0 / 40 · —
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

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Noroxi analysis

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Affected systems

Is your version affected?

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—

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

    • 5dfd283f4651d04dbb70ceb9ae5c4a30eda3c52a, de7921631ff323369aa63a4324695ab54ea4047e, 6.10affected
    • 4090fa373f0e763c43610853d2774b5979915959 and later · before b8f71d69380a5fbc734c868acbeb560f1de1766faffected · git
    • 4090fa373f0e763c43610853d2774b5979915959 and later · before be550ee108ad80828aa61280400bedfc7e7c39d3affected · git
    • 4090fa373f0e763c43610853d2774b5979915959 and later · before 4a4263dfeabad72f95e8ab6e15146861fa4144ddaffected · git
    • 6.1.141 and later · before 6.2affected · semver
    • 6.6.93 and later · before 6.7affected · semver
    • before 6.10not affected · semver
    • 6.18.54 and later · up to and including 6.18.*not affected · semver
    • 7.2.8 and later · up to and including 7.2.*not affected · semver
    • 7.3 and laternot affected · original_commit_for_fix

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxfrom 0—
Debian:14linuxbefore 7.2.8-17.2.8-1

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-2026-98287Oct 6, 2026 · pppoatm: ensure a writable skb header and linear data
    0Monitor
  • ← EarlierCVE-2026-98288Oct 6, 2026 · net: stmmac: fix TSO header length truncation
    0Monitor
  • Later →CVE-2026-98290Oct 6, 2026 · Bluetooth: RFCOMM: avoid socket lock inversion in listener cleanup
    30Monitor

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 Linux4a4263dfeabad72f95e8ab6e15146861fa4144ddVendor (CNA)
Linux Linux6.2Vendor (CNA)
Linux Linux6.7Vendor (CNA)
Linux Linuxb8f71d69380a5fbc734c868acbeb560f1de1766fVendor (CNA)
Linux Linuxbe550ee108ad80828aa61280400bedfc7e7c39d3Vendor (CNA)
azl3 kernel 6.6.157.1-1 on Azure Linux 3.06.6.159.1-1 · Release NotesMicrosoft (MSRC)
debian:linux7.2.8-1 · Debian:14Package registry (OSV)

Exploit status

No known public exploit

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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 7, 2026+32 d
EPSS, last 120 days

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

Patch and commit links

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No commit or PR link among the references.

Credits

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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).

Technical details

No CVSS vector for this record, so attack conditions can't be derived.

Weakness class (CWE)

—

Attack context

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Change log

  1. Exploit maturity— → none
  2. Fix✗ → ✓

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References

Show all references (2 more)

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

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