CVE-2026-74646

Local privilege escalation via unsynchronized FastRPC mmap moves

Published Aug 22, 2026 · Updated Aug 25, 2026

Race condition in the FastRPC driver in affected Linux kernels allows local users to gain kernel privileges through concurrent ioctls. The fastrpc_internal_invoke() error path moves fl->mmaps entries after an interrupted invoke without taking fl->lock, racing mmap or munmap operations and corrupting kernel list and heap state. Exploitation requires local access to a FastRPC device node and coordinated invoke, signal, and mmap or munmap ioctls; success can disclose or overwrite kernel memory or crash the system.

CVSS severity7.8
High
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Race condition in the FastRPC driver in affected Linux kernels allows local users to gain kernel privileges through concurrent ioctls. The fastrpc_internal_invoke() error path moves fl->mmaps entries after an interrupted invoke without taking fl->lock, racing mmap or munmap operations and corrupting kernel list and heap state. Exploitation requires local access to a FastRPC device node and coordinated invoke, signal, and mmap or munmap ioctls; success can disclose or overwrite kernel memory or crash the system.

The record

CVE
CVE-2026-74646
Published
Aug 22, 2026
Updated
Aug 25, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-414, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 22, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 25, 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=6.2
  2. Affected versionversion=76e8e4ace1ed2c97dba3b1370e0e105e07c572bc <3f265e405e5ef85030c3777262e18bb556bc8724
  3. Affected versionversion=76e8e4ace1ed2c97dba3b1370e0e105e07c572bc <a902fe1f80f58a2335b6be1131866f827ec44d1a
  4. Affected versionversion=76e8e4ace1ed2c97dba3b1370e0e105e07c572bc <af6345159abcbaa550518f31990d2a9558c2d369
  5. Affected versionversion=76e8e4ace1ed2c97dba3b1370e0e105e07c572bc <b85a0e91d7d6cd06a53c881a46f749cfcef416a2
  6. Affected versionversion=76e8e4ace1ed2c97dba3b1370e0e105e07c572bc <efd02f8d1a7449f15809bc18d3cd41aafea75d7e

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=6.2; version=76e8e4ace1ed2c97dba3b1370e0e105e07c572bc <3f265e405e5ef85030c3777262e18bb556bc8724; version=76e8e4ace1ed2c97dba3b1370e0e105e07c572bc <a902fe1f80f58a2335b6be1131866f827ec44d1a; version=76e8e4ace1ed2c97dba3b1370e0e105e07c572bc <af6345159abcbaa550518f31990d2a9558c2d369; version=76e8e4ace1ed2c97dba3b1370e0e105e07c572bc <b85a0e91d7d6cd06a53c881a46f749cfcef416a2; version=76e8e4ace1ed2c97dba3b1370e0e105e07c572bc <efd02f8d1a7449f15809bc18d3cd41aafea75d7e

Published CVSS scores

5.5Red HatCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
7.8Linux CVE TeamCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.8CanonicalCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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

CWE-414Missing Lock Check
T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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