CVE-2026-63816

Local privilege escalation via unreferenced atomic inode

Published Jul 19, 2026 · Updated Jul 19, 2026

Use-after-free in F2FS in affected Linux Kernel releases allows local users to corrupt kernel memory through atomic-write activity. During garbage collection, ra_data_block() reads fi->atomic_inode->i_mapping without holding a reference while f2fs_evict_inode() can clear and free the atomic inode. An unprivileged user with write access to files on an F2FS mount can race atomic writes, inode eviction, and garbage collection, causing a kernel panic or local privilege escalation.

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

Use-after-free in F2FS in affected Linux Kernel releases allows local users to corrupt kernel memory through atomic-write activity. During garbage collection, ra_data_block() reads fi->atomic_inode->i_mapping without holding a reference while f2fs_evict_inode() can clear and free the atomic inode. An unprivileged user with write access to files on an F2FS mount can race atomic writes, inode eviction, and garbage collection, causing a kernel panic or local privilege escalation.

The record

CVE
CVE-2026-63816
Published
Jul 19, 2026
Updated
Jul 19, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 19, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 19, 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=3db1de0e582c358dd013f3703cd55b5fe4076436 <56038756aae68312df00d4aa1d97e51ef3aca725
  2. Affected versionversion=3db1de0e582c358dd013f3703cd55b5fe4076436 <a499f77c06050a28c897bdbd86cd2f0721ae0743
  3. Affected versionversion=3db1de0e582c358dd013f3703cd55b5fe4076436 <a805fec35c201c59643ddcde713bce4051c8ee27
  4. Affected versionversion=3db1de0e582c358dd013f3703cd55b5fe4076436 <e0288584baa5dc41df4a829a023c4c1b33fe53d7
  5. Affected versionversion=5.18.18 <5.19
  6. Affected versionversion=5.19
  7. Affected versionversion=6db52f1944417c2601182a591a704e2f119c5215

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=3db1de0e582c358dd013f3703cd55b5fe4076436 <56038756aae68312df00d4aa1d97e51ef3aca725; version=3db1de0e582c358dd013f3703cd55b5fe4076436 <a499f77c06050a28c897bdbd86cd2f0721ae0743; version=3db1de0e582c358dd013f3703cd55b5fe4076436 <a805fec35c201c59643ddcde713bce4051c8ee27; version=3db1de0e582c358dd013f3703cd55b5fe4076436 <e0288584baa5dc41df4a829a023c4c1b33fe53d7; version=5.18.18 <5.19; version=5.19; version=6db52f1944417c2601182a591a704e2f119c5215

Published CVSS scores

7.8Linux kernel CNACVSS: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 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

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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