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Fencer Vulns
high 8.8

CVE-2024-26689 json

ceph: prevent use-after-free in encode_cap_msg()

published 2024-04-03 2 y ago modified 2026-08-05 3 mo ago also EUVD-2024-23951

cvss
8.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.7%
EPSS 0.7% chance of exploitation in 30 days, percentile 53%
public exploits
0
none known

Summary

In the Linux kernel, the following vulnerability has been resolved:

ceph: prevent use-after-free in encode_cap_msg()

In fs/ceph/caps.c, in encode_cap_msg(), "use after free" error was caught by KASAN at this line - 'ceph_buffer_get(arg->xattr_buf);'. This implies before the refcount could be increment here, it was freed.

In same file, in "handle_cap_grant()" refcount is decremented by this line - 'ceph_buffer_put(ci->i_xattrs.blob);'. It appears that a race occurred and resource was freed by the latter line before the former line could increment it.

encode_cap_msg() is called by __send_cap() and __send_cap() is called by ceph_check_caps() after calling __prep_cap(). __prep_cap() is where arg->xattr_buf is assigned to ci->i_xattrs.blob. This is the spot where the refcount must be increased to prevent "use after free" error.

Patch / fix

  • Linux Linux 5.10.210, 5.15.149, 6.1.79, 6.6.18, 6.7.6, 6.8
  • linux Debian 12 6.1.82-1
  • linux Debian 14, Debian 13 6.7.7-1

debian advisories DEBIAN-CVE-2024-26689

  • linux Ubuntu 20.04 LTS 5.4.0-215.235
  • linux Ubuntu 22.04 LTS 5.15.0-106.116
  • linux-aws Ubuntu 20.04 LTS 5.4.0-1145.155
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1061.67
  • linux-gcp Ubuntu 20.04 LTS 5.4.0-1148.157
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1059.67
  • linux-gke Ubuntu 22.04 LTS 5.15.0-1058.63
  • linux-ibm Ubuntu 20.04 LTS 5.4.0-1091.96

ubuntu advisories UBUNTU-CVE-2024-26689

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel-syms SLES for SAP 12 SP5, SLES 12 SP5 4.12.14-122.216.1
  • kernel-source SLES for SAP 12 SP5, SLES 12 SP5 4.12.14-122.216.1
  • kernel-default SLES for SAP 12 SP5, SLES 12 SP5, SLE Workstation Extension 12 SP5 +2 more 4.12.14-122.216.1
  • kernel-obs-build SLE Software Development Kit 12 SP5 4.12.14-122.216.1
  • kernel-rt SLE Micro 5.5, Real Time Module 15 SP5, openSUSE Leap 15.5 5.14.21-150500.13.52.1
  • kernel-syms-rt Real Time Module 15 SP5, openSUSE Leap 15.5 5.14.21-150500.13.52.1
  • kernel-rt_debug Real Time Module 15 SP5, openSUSE Leap 15.5 5.14.21-150500.13.52.1
  • kernel-source-rt SLE Micro 5.5, Real Time Module 15 SP5, openSUSE Leap 15.5 5.14.21-150500.13.52.1

suse advisories SUSE-SU-2024:1870-1SUSE-SU-2024:1663-1SUSE-SU-2024:1659-1SUSE-SU-2024:1650-1SUSE-SU-2024:1647-1SUSE-SU-2024:1646-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2024-26689 updated cvss 6.3

kernel: ceph: prevent use-after-free in encode_cap_msg()

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more
    affected: no fix planned “Will not fix”
  • Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more
    affected: no fix available, no fix planned “Will not fix”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2 y ago

Exploit prediction

0.70% chance of exploitation in the next 30 days, higher than 53% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Linux Linux

Classification

Weakness
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.