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NVD / CVE Program· CNA Linux

CVE-2026-89439: platform/x86: ISST: Add a NULL check for sst_inst[]

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: 0.20% (FIRST EPSS).
  • Fixed version: Linux Linux 3de2776e9d7073765c10c2326c2bda5926811ea6, 49a95fe1f64f41c2e8959e525aefdb10f23b293e, c280fcd53b938b70c7dee9ce1a66b32bd6e5ebaa.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 3de2776e9d7073765c10c2326c2bda5926811ea6, 49a95fe1f64f41c2e8959e525aefdb10f23b293e, c280fcd53b938b70c7dee9ce1a66b32bd6e5ebaa 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: platform/x86: ISST: Add a NULL check for sst_inst[] To be consistent with other places, add a NULL check for failed socket loading by checking isst_common.sst_inst[].

—No exploit Fix available
Published
Sep 11, 2026
Updated
Oct 21, 2026
EPSS
0.2% · 10th 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 · 0.2%

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.

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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

    • 6.4affected
    • d805456c712f93ba8a012430f2a93bec133b6ff4 and later · before f7c9370dd1d3cedb80c635528271cab1d0bcb103affected · git
    • d805456c712f93ba8a012430f2a93bec133b6ff4 and later · before 49a95fe1f64f41c2e8959e525aefdb10f23b293eaffected · git
    • d805456c712f93ba8a012430f2a93bec133b6ff4 and later · before c280fcd53b938b70c7dee9ce1a66b32bd6e5ebaaaffected · git
    • d805456c712f93ba8a012430f2a93bec133b6ff4 and later · before ef7975af15126dd70ace519da7bb33f2848b9064affected · git
    • d805456c712f93ba8a012430f2a93bec133b6ff4 and later · before 3de2776e9d7073765c10c2326c2bda5926811ea6affected · git
    • before 6.4not affected · semver
    • 6.6.160 and later · up to and including 6.6.*not affected · semver
    • 6.12.109 and later · up to and including 6.12.*not affected · semver
    • 6.18.50 and later · up to and including 6.18.*not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linux-6.12before 6.12.111-1~deb12u16.12.111-1~deb12u1
Debian:13linuxbefore 6.12.111-16.12.111-1
Debian:14linuxbefore 7.2.6-17.2.6-1

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-2026-89437Sep 11, 2026 · platform/x86: int1092: Fix potential memory leak in sar_probe()
    0Monitor
  • ← EarlierCVE-2026-89438Sep 11, 2026 · platform/x86: ISST: Validate logical CPU id and clos id
    0Monitor
  • Later →CVE-2026-89440Sep 11, 2026 · mmc: via-sdmmc: stop card-detect handling on probe failure
    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 Linux3de2776e9d7073765c10c2326c2bda5926811ea6Vendor (CNA)
Linux Linux49a95fe1f64f41c2e8959e525aefdb10f23b293eVendor (CNA)
Linux Linuxc280fcd53b938b70c7dee9ce1a66b32bd6e5ebaaVendor (CNA)
Linux Linuxef7975af15126dd70ace519da7bb33f2848b9064Vendor (CNA)
Linux Linuxf7c9370dd1d3cedb80c635528271cab1d0bcb103Vendor (CNA)
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.

—

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

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

Weakness class (CWE)

—

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 (4 more)

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

All records