CVE-2024-26689: Debian Linux

High severity, CVSS 7.8. EPSS: 0.7% chance of exploitation in the next 30 days.

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.

Affected products

• Debian Debian Linux: version 10.0 only
• Linux Linux Kernel: before 5.10.210 (fixed in 5.10.210); from 5.11, before 5.15.149 (fixed in 5.15.149); from 5.16, before 6.1.79 (fixed in 6.1.79); from 6.2, before 6.6.18 (fixed in 6.6.18); from 6.7, before 6.7.6 (fixed in 6.7.6); version 6.8 only

Published 2024-04-03. Last modified 2026-08-04.