CVE-2026-89793Hinoki check available

Local command-buffer corruption via mprotect permission upgrade

Published Sep 16, 2026 · Updated Sep 16, 2026

Memory-protection bypass in Linux ublk allows local users to corrupt kernel-written command descriptors through a read-only mapping. ublk_ch_mmap rejects VM_WRITE but leaves VM_MAYWRITE set, so mprotect can upgrade the mapping and alter ublksrv_io_desc fields. A userspace ublk daemon with local device access must create the mapping; the documented result is descriptor corruption, not code execution.

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

What happened

Memory-protection bypass in Linux ublk allows local users to corrupt kernel-written command descriptors through a read-only mapping. ublk_ch_mmap rejects VM_WRITE but leaves VM_MAYWRITE set, so mprotect can upgrade the mapping and alter ublksrv_io_desc fields. A userspace ublk daemon with local device access must create the mapping; the documented result is descriptor corruption, not code execution.

The record

CVE
CVE-2026-89793
Published
Sep 16, 2026
Updated
Sep 16, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
local
Privileges
authenticated

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=0 <6.12.110
  2. Affected versionversion=0 <6.18.51
  3. Affected versionversion=0 <6.6.157
  4. Affected versionversion=0 <7.2.5
  5. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <5befd06a72216869b607cf7724a4f16c6a2d3999
  6. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <6e2b571b0a54755b06e092501913e1dfefe75d6c
  7. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <be41733c24be58e2a1ef718c80fafdfb98a40d5e
  8. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <e373c1acdbcf88cec533ece9f589020adaed0a78
  9. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <fa5e1bc673ca59722608af67b27e65dba0c97926

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=0 <6.12.110; version=0 <6.18.51; version=0 <6.6.157; version=0 <7.2.5; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <5befd06a72216869b607cf7724a4f16c6a2d3999; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <6e2b571b0a54755b06e092501913e1dfefe75d6c; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <be41733c24be58e2a1ef718c80fafdfb98a40d5e; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <e373c1acdbcf88cec533ece9f589020adaed0a78; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <fa5e1bc673ca59722608af67b27e65dba0c97926

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
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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