CVE-2026-80561

Status: UPDATED  |  Advisory ID: CVE-2026-80561

Key Details

Affected Products, Subsystems & Sectors

What to Know

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

libceph: fix multiple unsafe decodes in decode_locker()

decode_locker() in cls_lock_client.c contains three unsafe decode

operations that allow a malicious or compromised OSD to trigger

slab-out-of-bounds reads:

1. ceph_decode_copy() at the locker_id_t name field has no preceding

bounds check. With p == end after ceph_start_decoding() accepts

struct_len=0, this reads sizeof(ceph_entity_name) = 9 bytes past

the validated buffer boundary.

2. *p += sizeof(struct ceph_timespec) after the locker_info_t header

is an unchecked pointer advance. A malicious OSD can position p

past end, causing all subsequent _safe checks to pass against a

bogus boundary.

3. len = ceph_decode_32(p) has no preceding bounds check, and the

immediately following *p += len is uncapped. A malicious OSD can

send len=0xffffffff, advancing p gigabytes past end and escaping

the decode window entirely.

Fix all three by replacing bare operations with their safe variants:

ceph_decode_copy -> ceph_decode_copy_safe

*p += sizeof(...) -> ceph_decode_skip_n

ceph_decode_32(p) -> ceph_decode_32_safe

*p += len -> ceph_decode_skip_n

A new label is added to return -EINVAL on any bounds violation.

-EINVAL is appropriate here: the data received from the OSD

is structurally malformed, which is an invalid argument to the decode

contract regardless of whether the caller or the wire is at fault.

Attacker model: a malicious or compromised OSD in a multi-tenant Ceph

deployment can trigger this against any kernel client that issues the

lock.get_info class method (e.g. during RBD exclusive lock acquisition)

without any further privileges beyond OSD session establishment.

[ idryomov: use ceph_decode_skip_string() to skip description, trim

changelog ] (NVD)

What to Do

Monitor Linux's web page for any future patch releases.

References