ceph: lock mutex in ceph_mds_check_access()
Affects the Linux kernel Ceph client from 6.10.0 until the fixed releases 6.12.110, 6.18.51, and 7.2.5 for each branch. No vendor severity is given; CVSS rates it critical at 9.8.
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Unclear
- Fix
- Fixed in 6.12.110, 6.18.51, 7.2.5
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
The Linux kernel's Ceph distributed filesystem client is affected. A race condition in access checking can let a concurrent session reopen free memory that is still being read, which may crash the system or cause memory corruption.
Summarized by anthropic/claude-haiku-5.5. Verify details against the original sources.
Read the original description
In the Linux kernel, the following vulnerability has been resolved: ceph: lock mutex in ceph_mds_check_access() MDS session OPEN handling replaces mdsc->s_cap_auths under mdsc->mutex, freeing the previous array and its strings. ceph_mds_check_access() traverses this array without holding the mutex. A concurrent session reopen can therefore free the array while it is being inspected, resulting in a use-after-free like this: Unable to handle kernel paging request at virtual address 003aaad64b2c8bb9 [...] Internal error: Oops: 0000000096000004 [#1] SMP Modules linked in: CPU: 56 UID: 2953037534 PID: 1253231 Comm: php-cgi8.4 Not tainted 6.18.45-i2-ampere #1146 NONE [..] pc : ceph_mds_check_access+0xd4/0x550 lr : ceph_mds_check_access+0xc8/0x550 [...] Call trace: ceph_mds_check_access+0xd4/0x550 (P) ceph_atomic_open+0x138/0xbe8 path_openat+0xa24/0xfa8 do_filp_open+0x94/0x158 do_sys_openat2+0x88/0xf8
Timeline
- CVE published
- Record last updated
Affected versions
- Linux Linux
From 596afb0b8933ba6ed7227adcc538db26feb25c74 · fixed in 729c1ff670ece6f3d4b1738365a0b2f90d487523; From 596afb0b8933ba6ed7227adcc538db26feb25c74 · fixed in ca5bfea2045ef2eb3305cf2a9d8da549b76c37d3; From 596afb0b8933ba6ed7227adcc538db26feb25c74 · fixed in df1a97d5313fccadb08390306d49b194fb027392; From 596afb0b8933ba6ed7227adcc538db26feb25c74 · fixed in a61c6ae1dae2611082b831b4aaa780878099c012
- Linux Linux
6.10
- KernelLinux
From 6.10.0 · fixed in 6.12.110; From 6.13.0 · fixed in 6.18.51; From 6.19.0 · fixed in 7.2.5
References 4
Questions about CVE-2026-89990
What does this mean?
A concurrent MDS session reopen can free the s_cap_auths array while ceph_mds_check_access() is still traversing it. This use-after-free in the Ceph client can crash the kernel.Source: git.kernel.org
Am I affected, and how do I check?
The listed ranges start at Linux kernel 6.10.0, 6.13.0, and 6.19.0, and end at the fixed versions 6.12.110, 6.18.51, and 7.2.5 for each branch. Compare the output of uname -r against these ranges, and note that the flaw needs the Ceph kernel client and a concurrent MDS session reopen.Source: git.kernel.org
What should I do about it?
Move to a kernel at or past the fix for your branch: 6.12.110 or later for 6.12, 6.18.51 or later for 6.18, or 7.2.5 or later for 7.2.Source: git.kernel.org
Is it being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data