CVE-2026-64426

Kernel memory leak via mismatched file-reference flags

Published Jul 25, 2026 · Updated Jul 25, 2026

A resource leak in the io_uring NOP handler in Linux Kernel allows local users to consume kernel memory through crafted requests. The io_nop() path obtains a normal file reference when IOSQE_FIXED_FILE is set without IORING_NOP_FIXED_FILE, but io_put_file() treats the request as fixed and never releases that reference. Exploitation requires local access to submit the conflicting NOP flags; repeated requests accumulate unreleased file objects, with no published privilege-escalation or data-access impact.

CVSS severity5.5
Medium
EPSS probability0.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A resource leak in the io_uring NOP handler in Linux Kernel allows local users to consume kernel memory through crafted requests. The io_nop() path obtains a normal file reference when IOSQE_FIXED_FILE is set without IORING_NOP_FIXED_FILE, but io_put_file() treats the request as fixed and never releases that reference. Exploitation requires local access to submit the conflicting NOP flags; repeated requests accumulate unreleased file objects, with no published privilege-escalation or data-access impact.

The record

CVE
CVE-2026-64426
Published
Jul 25, 2026
Updated
Jul 25, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499.001
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 25, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 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=6.13
  2. Affected versionversion=a85f31052bce52111b4e9d5a536003481d0421d0 <2564ca2e31bd8ee8348362941af2ee4671e487ca
  3. Affected versionversion=a85f31052bce52111b4e9d5a536003481d0421d0 <722869fcff598fad20d5ab79c305897a7534708b
  4. Affected versionversion=a85f31052bce52111b4e9d5a536003481d0421d0 <7267717f35787167fcce4bc14f6ef3fa06682dcf

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=6.13; version=a85f31052bce52111b4e9d5a536003481d0421d0 <2564ca2e31bd8ee8348362941af2ee4671e487ca; version=a85f31052bce52111b4e9d5a536003481d0421d0 <722869fcff598fad20d5ab79c305897a7534708b; version=a85f31052bce52111b4e9d5a536003481d0421d0 <7267717f35787167fcce4bc14f6ef3fa06682dcf

Published CVSS scores

5.5Amazon LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.001OS Exhaustion Flood

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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