CVE-2024-26689

Local privilege escalation via CephFS refcount race

Published Apr 3, 2024 · Updated Aug 5, 2026

Use-after-free in the Linux kernel CephFS client allows local users to corrupt kernel memory during concurrent capability handling. __prep_cap() copied ci->i_xattrs.blob into the outgoing message without first acquiring a reference, while handle_cap_grant() could release that buffer before encode_cap_msg() called ceph_buffer_get(). The local low-privilege path requires an active CephFS client and grants elevated privileges on successful exploitation.

CVSS severity7.8
High
EPSS probability0.70%
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 the Linux kernel CephFS client allows local users to corrupt kernel memory during concurrent capability handling. __prep_cap() copied ci->i_xattrs.blob into the outgoing message without first acquiring a reference, while handle_cap_grant() could release that buffer before encode_cap_msg() called ceph_buffer_get(). The local low-privilege path requires an active CephFS client and grants elevated privileges on successful exploitation.

The record

CVE
CVE-2024-26689
Published
Apr 3, 2024
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-416, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 3, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 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=2.6.34
  2. Affected versionversion=9030aaf9bf0a1eee47a154c316c789e959638b0f <70e329b440762390258a6fe8c0de93c9fdd56c77
  3. Affected versionversion=9030aaf9bf0a1eee47a154c316c789e959638b0f <7958c1bf5b03c6f1f58e724dbdec93f8f60b96fc
  4. Affected versionversion=9030aaf9bf0a1eee47a154c316c789e959638b0f <8180d0c27b93a6eb60da1b08ea079e3926328214
  5. Affected versionversion=9030aaf9bf0a1eee47a154c316c789e959638b0f <ae20db45e482303a20e56f2db667a9d9c54ac7e7
  6. Affected versionversion=9030aaf9bf0a1eee47a154c316c789e959638b0f <cda4672da1c26835dcbd7aec2bfed954eda9b5ef
  7. Affected versionversion=9030aaf9bf0a1eee47a154c316c789e959638b0f <f3f98d7d84b31828004545e29fd7262b9f444139

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=2.6.34; version=9030aaf9bf0a1eee47a154c316c789e959638b0f <70e329b440762390258a6fe8c0de93c9fdd56c77; version=9030aaf9bf0a1eee47a154c316c789e959638b0f <7958c1bf5b03c6f1f58e724dbdec93f8f60b96fc; version=9030aaf9bf0a1eee47a154c316c789e959638b0f <8180d0c27b93a6eb60da1b08ea079e3926328214; version=9030aaf9bf0a1eee47a154c316c789e959638b0f <ae20db45e482303a20e56f2db667a9d9c54ac7e7; version=9030aaf9bf0a1eee47a154c316c789e959638b0f <cda4672da1c26835dcbd7aec2bfed954eda9b5ef; version=9030aaf9bf0a1eee47a154c316c789e959638b0f <f3f98d7d84b31828004545e29fd7262b9f444139

Published CVSS scores

7.8NIST NVDCVSS: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-416Use After Free
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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