CVE-2026-63817

Local privilege escalation via invalid F2FS meta inode

Published Jul 19, 2026 · Updated Jul 19, 2026

Improper inode validation in affected Linux Kernel releases allows local users to compromise kernel data and cause a service interrupt. When F2FS compress_cache is disabled, is_meta_ino() still classifies max_nid as the synthetic cache inode, so f2fs_iget() bypasses do_read_inode() and its range check. Exploitation requires low-privileged local access and a corrupted F2FS directory entry whose inode equals max_nid; the resulting fake internal inode exposes kernel confidentiality, integrity, and availability.

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

Improper inode validation in affected Linux Kernel releases allows local users to compromise kernel data and cause a service interrupt. When F2FS compress_cache is disabled, is_meta_ino() still classifies max_nid as the synthetic cache inode, so f2fs_iget() bypasses do_read_inode() and its range check. Exploitation requires low-privileged local access and a corrupted F2FS directory entry whose inode equals max_nid; the resulting fake internal inode exposes kernel confidentiality, integrity, and availability.

The record

CVE
CVE-2026-63817
Published
Jul 19, 2026
Updated
Jul 19, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-358, 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

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5.13.19 <5.14
  2. Affected versionversion=5.14
  3. Affected versionversion=6ce19aff0b8cd386860855185c6cd79337fc4d2b <0969926d987bbde9a1aa49da317582ba37095805
  4. Affected versionversion=6ce19aff0b8cd386860855185c6cd79337fc4d2b <13e4b59d3a9413f66f116fa6c4828519b960a5ea
  5. Affected versionversion=6ce19aff0b8cd386860855185c6cd79337fc4d2b <16161444c30d8dff9428abbae42b72ce4e32a932
  6. Affected versionversion=6ce19aff0b8cd386860855185c6cd79337fc4d2b <29115b8c9172d34e67ab26cc4f6c209b7a236d7a
  7. Affected versionversion=6ce19aff0b8cd386860855185c6cd79337fc4d2b <5073c66a96a9c23c0c2533ed4ed06e42f9021208
  8. Affected versionversion=6ce19aff0b8cd386860855185c6cd79337fc4d2b <77f216ff9ce5cde8eed9f6d12707e906dffdc9f7
  9. Affected versionversion=a23706426da9b611be5beae0f3faa260fb453b4e

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=5.13.19 <5.14; version=5.14; version=6ce19aff0b8cd386860855185c6cd79337fc4d2b <0969926d987bbde9a1aa49da317582ba37095805; version=6ce19aff0b8cd386860855185c6cd79337fc4d2b <13e4b59d3a9413f66f116fa6c4828519b960a5ea; version=6ce19aff0b8cd386860855185c6cd79337fc4d2b <16161444c30d8dff9428abbae42b72ce4e32a932; version=6ce19aff0b8cd386860855185c6cd79337fc4d2b <29115b8c9172d34e67ab26cc4f6c209b7a236d7a; version=6ce19aff0b8cd386860855185c6cd79337fc4d2b <5073c66a96a9c23c0c2533ed4ed06e42f9021208; version=6ce19aff0b8cd386860855185c6cd79337fc4d2b <77f216ff9ce5cde8eed9f6d12707e906dffdc9f7; version=a23706426da9b611be5beae0f3faa260fb453b4e

Published CVSS scores

7.8LinuxCVSS: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

CWE-358Improperly Implemented Security Check for Standard
T1068Exploitation for Privilege Escalation

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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