CVE-2026-63814

Kernel data disclosure via truncated f2fs ACL entry

Published Jul 19, 2026 · Updated Jul 19, 2026

Out-of-bounds read in Linux Kernel f2fs ACL parsing allows local users to disclose adjacent kernel heap data via a malformed ACL. f2fs_acl_from_disk() reads entry->e_id from ACL_USER or ACL_GROUP records after checking only the aggregate xattr length, so a short-entry slot causes a four-byte slab over-read. Planting the malformed on-disk ACL requires a crafted f2fs image and mount capability or raw block-device access; triggering then requires read access to the inode and can expose sensitive kernel memory or destabilize 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

Out-of-bounds read in Linux Kernel f2fs ACL parsing allows local users to disclose adjacent kernel heap data via a malformed ACL. f2fs_acl_from_disk() reads entry->e_id from ACL_USER or ACL_GROUP records after checking only the aggregate xattr length, so a short-entry slot causes a four-byte slab over-read. Planting the malformed on-disk ACL requires a crafted f2fs image and mount capability or raw block-device access; triggering then requires read access to the inode and can expose sensitive kernel memory or destabilize the system.

The record

CVE
CVE-2026-63814
Published
Jul 19, 2026
Updated
Jul 19, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-125
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=3.8
  2. Affected versionversion=af48b85b8cd3fbb12c9b6759c16db6d69c0b03da <1ddf3fd21c4c652f9cab5552515c04a166662306
  3. Affected versionversion=af48b85b8cd3fbb12c9b6759c16db6d69c0b03da <442ca20c54038e2400cf28aaa944cf1de2c8e65d
  4. Affected versionversion=af48b85b8cd3fbb12c9b6759c16db6d69c0b03da <4e2a96ec7236e248e706850568e0a925fd21b588
  5. Affected versionversion=af48b85b8cd3fbb12c9b6759c16db6d69c0b03da <5d8a39649947a4e86c8fbc682d7fc0041b8d109a
  6. Affected versionversion=af48b85b8cd3fbb12c9b6759c16db6d69c0b03da <733cd8474e6d763d75ed96f3f2b98a25480cf2b9
  7. Affected versionversion=af48b85b8cd3fbb12c9b6759c16db6d69c0b03da <aba4f94ac1832c7299c33e1b4fe5f87eef6dc8f1
  8. Affected versionversion=af48b85b8cd3fbb12c9b6759c16db6d69c0b03da <c4810ada31e80cbe4011467c4f3b1e93f94134f3
  9. Affected versionversion=af48b85b8cd3fbb12c9b6759c16db6d69c0b03da <ff83de56882cb8466184d322abece2589258ca56

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=3.8; version=af48b85b8cd3fbb12c9b6759c16db6d69c0b03da <1ddf3fd21c4c652f9cab5552515c04a166662306; version=af48b85b8cd3fbb12c9b6759c16db6d69c0b03da <442ca20c54038e2400cf28aaa944cf1de2c8e65d; version=af48b85b8cd3fbb12c9b6759c16db6d69c0b03da <4e2a96ec7236e248e706850568e0a925fd21b588; version=af48b85b8cd3fbb12c9b6759c16db6d69c0b03da <5d8a39649947a4e86c8fbc682d7fc0041b8d109a; version=af48b85b8cd3fbb12c9b6759c16db6d69c0b03da <733cd8474e6d763d75ed96f3f2b98a25480cf2b9; version=af48b85b8cd3fbb12c9b6759c16db6d69c0b03da <aba4f94ac1832c7299c33e1b4fe5f87eef6dc8f1; version=af48b85b8cd3fbb12c9b6759c16db6d69c0b03da <c4810ada31e80cbe4011467c4f3b1e93f94134f3; version=af48b85b8cd3fbb12c9b6759c16db6d69c0b03da <ff83de56882cb8466184d322abece2589258ca56

Published CVSS scores

7.8Linux Kernel CVE TeamCVSS: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-125Out-of-bounds Read

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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