CVE-2026-89442

Local service interruption via unchecked ISST socket ID

Published Sep 11, 2026 · Updated Sep 11, 2026

Improper input validation in Linux allows local users to interrupt service through a crafted ISST CLOS association ioctl. isst_if_clos_assoc accepts a socket_id equal to the package count and also accepts packages with no bound TPMI SST instance, then dereferences the resulting out-of-bounds or NULL pointer. Reachability requires local ioctl access and Intel Speed Select Technology with the affected TPMI path; the resulting kernel fault can crash the host.

CVSS severityUnavailable
Unscored
EPSS probability0.16%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in Linux allows local users to interrupt service through a crafted ISST CLOS association ioctl. isst_if_clos_assoc accepts a socket_id equal to the package count and also accepts packages with no bound TPMI SST instance, then dereferences the resulting out-of-bounds or NULL pointer. Reachability requires local ioctl access and Intel Speed Select Technology with the affected TPMI path; the resulting kernel fault can crash the host.

The record

CVE
CVE-2026-89442
Published
Sep 11, 2026
Updated
Sep 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. Sep 11, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 11, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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  1. Affected versionversion=12a7d2cb811dd8a884dea088a2701fcb8d00136e <0d90ab5f80e19cddfeb0c9fab47a1f34aa932075
  2. Affected versionversion=12a7d2cb811dd8a884dea088a2701fcb8d00136e <207b4dc6eb100141b122b2602504a1429a4b6558
  3. Affected versionversion=12a7d2cb811dd8a884dea088a2701fcb8d00136e <82e707eff9e3b7ef6d96ecc23ea8876d20c7d6ca
  4. Affected versionversion=12a7d2cb811dd8a884dea088a2701fcb8d00136e <a89f07db0cb95c54dac4a8406c79a04e44a73c3c
  5. Affected versionversion=6.4

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=12a7d2cb811dd8a884dea088a2701fcb8d00136e <0d90ab5f80e19cddfeb0c9fab47a1f34aa932075; version=12a7d2cb811dd8a884dea088a2701fcb8d00136e <207b4dc6eb100141b122b2602504a1429a4b6558; version=12a7d2cb811dd8a884dea088a2701fcb8d00136e <82e707eff9e3b7ef6d96ecc23ea8876d20c7d6ca; version=12a7d2cb811dd8a884dea088a2701fcb8d00136e <a89f07db0cb95c54dac4a8406c79a04e44a73c3c; version=6.4

Published CVSS scores

No CVSS assessment is available in this record.

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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