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NVD / CVE Program· CNA Linux

CVE-2026-97940: ipv6: fix fib6 walker UAF on seq stop

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: 0.16% (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 05b687ee04f816658f4a9cf586f4d2f129157943, 0eede1689610e9eeaf729ba86fd1321799eb91a0, 14fdaba201fdff92a3e45994e02bccda409cb19d; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 6.6.158.1-1.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 05b687ee04f816658f4a9cf586f4d2f129157943, 0eede1689610e9eeaf729ba86fd1321799eb91a0, 14fdaba201fdff92a3e45994e02bccda409cb19d; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 6.6.158.1-1 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: ipv6: fix fib6 walker UAF on seq stop ipv6_route_iter_active() treats a walker in FWS_U at the table root as already unlinked. fib6_del_route() can move a still-linked walker into that same state when the current leaf is the last route at the root, so ipv6_route_native_seq_stop() skips fib6_walker_unlink(). The seq private object can then be freed while it remains on net->ipv6.fib6_walkers. A later route deletion walks the dangling list and uses the freed walker. Use the list head as membership state and reinitialize it when unlinking. Keep the existing w->node check so a never-started iterator with a zeroed private object is not treated as linked. The same stop helper is used by /proc/net/ipv6_route and by the BPF ipv6_route iterator. The BPF show path only widens the race.

HighCVSS 7.8 · v3.1—No exploit Fix available
Published
Sep 25, 2026
Updated
Oct 19, 2026
EPSS
0.1% · 6th 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

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When you'll hear from us

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  • when exploit code appears or is weaponized
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  • 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

    • 3.13affected
    • 8d2ca1d7b5c3e63b3a8a81ae99015b615c5f2bf7 and later · before 9a3f73d62c86271614eda4c43315230896a37018affected · git
    • 8d2ca1d7b5c3e63b3a8a81ae99015b615c5f2bf7 and later · before 63407cddabc5992b5ac03af165559f4a1968a032affected · git
    • 8d2ca1d7b5c3e63b3a8a81ae99015b615c5f2bf7 and later · before 05b687ee04f816658f4a9cf586f4d2f129157943affected · git
    • 8d2ca1d7b5c3e63b3a8a81ae99015b615c5f2bf7 and later · before 14fdaba201fdff92a3e45994e02bccda409cb19daffected · git
    • 8d2ca1d7b5c3e63b3a8a81ae99015b615c5f2bf7 and later · before 0eede1689610e9eeaf729ba86fd1321799eb91a0affected · git
    • 8d2ca1d7b5c3e63b3a8a81ae99015b615c5f2bf7 and later · before b89b691dd00bf39b9ba39ab9446f8c62f419fa7baffected · git
    • 8d2ca1d7b5c3e63b3a8a81ae99015b615c5f2bf7 and later · before 4553cfafa8d05c4ce20b1d18f79d9bb3b303fc02affected · git
    • 8d2ca1d7b5c3e63b3a8a81ae99015b615c5f2bf7 and later · before 19b4ed644d68098cc62ab612727f40d30f43476caffected · git
    • before 3.13not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.190-16.1.190-1
Debian:12linux-6.12before 6.12.111-1~deb12u16.12.111-1~deb12u1
Debian:13linuxbefore 6.12.111-16.12.111-1
Debian:14linuxbefore 7.2.7-17.2.7-1

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-2026-97938Sep 25, 2026 · reboot: fix cad_pid use-after-free race
    0Monitor
  • ← EarlierCVE-2026-97939Sep 25, 2026 · ipmr: account multicast table and route memory
    0Monitor
  • Later →CVE-2026-97941Sep 25, 2026 · mm/slab: take n->list_lock in __slab_try_return_freelist() to avoid race
    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 Linux05b687ee04f816658f4a9cf586f4d2f129157943Vendor (CNA)
Linux Linux0eede1689610e9eeaf729ba86fd1321799eb91a0Vendor (CNA)
Linux Linux14fdaba201fdff92a3e45994e02bccda409cb19dVendor (CNA)
Linux Linux19b4ed644d68098cc62ab612727f40d30f43476cVendor (CNA)
Linux Linux4553cfafa8d05c4ce20b1d18f79d9bb3b303fc02Vendor (CNA)
Linux Linux63407cddabc5992b5ac03af165559f4a1968a032Vendor (CNA)
Linux Linux9a3f73d62c86271614eda4c43315230896a37018Vendor (CNA)
Linux Linuxb89b691dd00bf39b9ba39ab9446f8c62f419fa7bVendor (CNA)
azl3 kernel 6.6.157.1-1 on Azure Linux 3.06.6.158.1-1 · Release NotesMicrosoft (MSRC)
debian:linux6.1.190-1 · Debian:12Package registry (OSV)
debian:linux6.12.111-1 · Debian:13Package registry (OSV)
debian:linux-6.126.12.111-1~deb12u1 · Debian:12Package 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.

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.

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.

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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. 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