CVE-2026-89787

Kernel out-of-bounds read via truncated hash trailer

Published Sep 16, 2026 · Updated Sep 16, 2026

An out-of-bounds read in Linux 5.13 and affected git revisions allows local users to trigger a kernel memory fault via a crafted ext4 entry. The ext4_search_dir() pre-check validates only the raw name length, then ext4_match() reads an eight-byte hash trailer rounded beyond the directory-block boundary. Reachability requires a casefolded encrypted ext4 directory on the compatibility-fallback-disabled path and a lookup of the crafted entry; no broader impact is established.

CVSS severityUnavailable
Unscored
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

An out-of-bounds read in Linux 5.13 and affected git revisions allows local users to trigger a kernel memory fault via a crafted ext4 entry. The ext4_search_dir() pre-check validates only the raw name length, then ext4_match() reads an eight-byte hash trailer rounded beyond the directory-block boundary. Reachability requires a casefolded encrypted ext4 directory on the compatibility-fallback-disabled path and a lookup of the crafted entry; no broader impact is established.

The record

CVE
CVE-2026-89787
Published
Sep 16, 2026
Updated
Sep 16, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. Sep 16, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=471fbbea7ff7061b2d6474665cb5a2ceb4fd6500 <3933884bc3102898b458c53fbd1ac52eb9cdb8a4
  2. Affected versionversion=471fbbea7ff7061b2d6474665cb5a2ceb4fd6500 <4d20106c536b73c4a8a02652dc85e35898baebf7
  3. Affected versionversion=471fbbea7ff7061b2d6474665cb5a2ceb4fd6500 <61a395967de06edba58760e81907a272db749faa
  4. Affected versionversion=471fbbea7ff7061b2d6474665cb5a2ceb4fd6500 <83663c0b739480c00cfe785675db87520ec484ed
  5. Affected versionversion=471fbbea7ff7061b2d6474665cb5a2ceb4fd6500 <c7e6b863d298f56522d0d08554bbea7f142e6588
  6. Affected versionversion=471fbbea7ff7061b2d6474665cb5a2ceb4fd6500 <d8c184bec24b5a00ae96d704856d935eaded1685
  7. Affected versionversion=471fbbea7ff7061b2d6474665cb5a2ceb4fd6500 <e94676a08af6312aa72d8a981232b281f9bcfcf5
  8. Affected versionversion=5.13

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=471fbbea7ff7061b2d6474665cb5a2ceb4fd6500 <3933884bc3102898b458c53fbd1ac52eb9cdb8a4; version=471fbbea7ff7061b2d6474665cb5a2ceb4fd6500 <4d20106c536b73c4a8a02652dc85e35898baebf7; version=471fbbea7ff7061b2d6474665cb5a2ceb4fd6500 <61a395967de06edba58760e81907a272db749faa; version=471fbbea7ff7061b2d6474665cb5a2ceb4fd6500 <83663c0b739480c00cfe785675db87520ec484ed; version=471fbbea7ff7061b2d6474665cb5a2ceb4fd6500 <c7e6b863d298f56522d0d08554bbea7f142e6588; version=471fbbea7ff7061b2d6474665cb5a2ceb4fd6500 <d8c184bec24b5a00ae96d704856d935eaded1685; version=471fbbea7ff7061b2d6474665cb5a2ceb4fd6500 <e94676a08af6312aa72d8a981232b281f9bcfcf5; version=5.13

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

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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

No sourced classifications are available.

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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