CVE-2026-53303

Information disclosure via unlocked extension-list read

Published Jun 26, 2026 · Updated Jun 26, 2026

Out-of-bounds read in Linux Kernel F2FS affected branches allows local users to disclose kernel memory through a sysfs race. f2fs_sbi_show reads extension_list, extension_count, and hot_ext_count without sb_lock while f2fs_update_extension_list can modify them. Exploitation requires local access, an active F2FS instance, and concurrent access to its extension_list sysfs control; effects are bounded to stale-data disclosure or an out-of-bounds read.

CVSS severity7.1
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

Out-of-bounds read in Linux Kernel F2FS affected branches allows local users to disclose kernel memory through a sysfs race. f2fs_sbi_show reads extension_list, extension_count, and hot_ext_count without sb_lock while f2fs_update_extension_list can modify them. Exploitation requires local access, an active F2FS instance, and concurrent access to its extension_list sysfs control; effects are bounded to stale-data disclosure or an out-of-bounds read.

The record

CVE
CVE-2026-53303
Published
Jun 26, 2026
Updated
Jun 26, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-125
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 26, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 26, 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=4.17
  2. Affected versionversion=b6a06cbbb5f7fd03589cff9178314af04c568826 <4b3a1bf4c2ffd4c9595d900ead78c9035894a025
  3. Affected versionversion=b6a06cbbb5f7fd03589cff9178314af04c568826 <5909bedbed38c558bee7cb6758ceedf9bc3a9194
  4. Affected versionversion=b6a06cbbb5f7fd03589cff9178314af04c568826 <cea15f66b7b68b2c50943a6660e0692c6635e4eb
  5. Affected versionversion=b6a06cbbb5f7fd03589cff9178314af04c568826 <d0e877810baf613b018fd9747440b9d4d9db1428
  6. Affected versionversion=b6a06cbbb5f7fd03589cff9178314af04c568826 <d3ff0c121bbaef026df6248ab7ef6f0b068b0647
  7. Affected versionversion=b6a06cbbb5f7fd03589cff9178314af04c568826 <ea3ab43a1f3cf2c7cecd75c8be1ee99a5e94a92e

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=4.17; version=b6a06cbbb5f7fd03589cff9178314af04c568826 <4b3a1bf4c2ffd4c9595d900ead78c9035894a025; version=b6a06cbbb5f7fd03589cff9178314af04c568826 <5909bedbed38c558bee7cb6758ceedf9bc3a9194; version=b6a06cbbb5f7fd03589cff9178314af04c568826 <cea15f66b7b68b2c50943a6660e0692c6635e4eb; version=b6a06cbbb5f7fd03589cff9178314af04c568826 <d0e877810baf613b018fd9747440b9d4d9db1428; version=b6a06cbbb5f7fd03589cff9178314af04c568826 <d3ff0c121bbaef026df6248ab7ef6f0b068b0647; version=b6a06cbbb5f7fd03589cff9178314af04c568826 <ea3ab43a1f3cf2c7cecd75c8be1ee99a5e94a92e

Published CVSS scores

7.1NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/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

CWE-125Out-of-bounds Read

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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