CVE-2026-80561
CriticalCVSS 9.8Exploitation Probability (EPSS)
Low risk42th percentile - higher than 42% of all known CVEs
Summary
In the Linux kernel, the decode_locker() function in cls_lock_client.c contains three unsafe decode operations that allow a malicious or compromised OSD to trigger slab-out-of-bounds reads. Missing bounds checks before copying the name, an unchecked pointer advance, and an uncapped length value can lead to memory corruption. The fix replaces unsafe operations with safe variants and returns -EINVAL on any bounds violation.
Risk Assessment
A malicious OSD in a multi-tenant Ceph deployment can exploit this vulnerability to read kernel memory beyond the validated buffer, potentially leading to information disclosure or system instability. The vulnerability can be triggered by any kernel client issuing the lock.get_info class method, e.g., during RBD exclusive lock acquisition.
Recommendation
Apply the official Linux kernel patch that fixes decode_locker() immediately and update systems to a patched kernel version. Additionally, limit trust in OSDs and monitor OSD sessions for anomalous behavior.
Other vulnerabilities in Linux kernel
See all- CVE-2026-99270Unknown
A use-after-free (UAF) vulnerability exists in the Linux kernel's reqsk_timer_handler() function. When TCP socket migration fails at inet_ehash_insert(), the code jumps to the no_ownership label and immediately frees the new reqsk via __reqsk_free() without stopping its timer, potentially leading to a UAF.
- CVE-2026-99269Unknown
In the Linux kernel sched_ext scheduler, a task can be found on a non-local DSQ while the CPU that dispatched it is still running ops.dequeue() and hasn't cleared SCX_OPSS_DISPATCHING. The DSQ consume and move paths don't wait for dispatch to finish and can operate on the task concurrently with the dispatcher. The fix adds scx_wait_dispatching() before operating on the task.
- CVE-2026-99268Unknown
In io_uring with IORING_SETUP_DEFER_TASKRUN, completions are queued as local work and only become CQEs when the submitter enters the kernel to wait for events. io_uring_poll() reports EPOLLIN if local work is pending, but only if the work exists at call time; after DEFER_TASKRUN was added, the ->poll_wq wakeup was replaced by directly waking the submitter, so poll() can sleep despite pending work. The fix wakes ->poll_wq when the first entry is put on the work list, using an RCU callback when needed.
- CVE-2026-99267Unknown
In io_uring NAPI with dynamic tracking, a NAPI id not seen for a minute should be dropped from the ring's busy-poll list. However, the timeout is computed incorrectly — SEC_CONVERSION is used instead of the number of jiffies per second, giving about eight years for HZ=1000 and overflowing on 32-bit systems. As a result, entries are never removed and every wait polls all historical ids.
- CVE-2026-99266Unknown
In io_uring zcrx, io_zcrx_queue_cqe() computes the buffer offset in its area from net_iov_idx(), which is an unsigned int, so the shift is done in 32 bits and only the result is widened to the u64 placed in the CQE. An area can be up to 1 TB, so for every niov beyond the first 4 GB the CQE points the application at a buffer 4 GB (or a multiple) below the correct one. The application reads wrong data and returns a buffer it doesn't own via the refill queue while the real one is never given back.
- CVE-2026-99265Unknown
In io_uring/openclose, io_pipe_fixed() installs both ends of the pipe in the fixed file table, drops ->uring_lock, and copies the slot numbers to the application. If that faults, it takes the lock again and removes whatever is in these slots. If the request is run by io-wq, the lock really is dropped and the slots are visible to others; by the time the error path gets to them, they may have been closed and reused (by IORING_OP_CLOSE, direct open/accept, or IORING_REGISTER_FILES_UPDATE), causing removal of a file unrelated to the failed request. The fix performs the copy with the lock held.
- CVE-2026-99264Unknown
A bug was fixed in the Linux kernel's io_uring/net handling of recv retries on uncommitted buffers. When a receive was retried after a partial transfer, the kernel could hand out buffer memory that the retried request was still writing to, causing data overwrites. The request is now completed with the bytes received instead of retried, and MSG_WAITALL is no longer honoured for incremental buffers or multi-buffer bundles.
- CVE-2026-99263Unknown
In io_uring/poll, if a wakeup sets IO_POLL_RETRY_FLAG between the owning task consuming the existing instance of IO_POLL_RETRY_FLAG and the loop check in io_poll_check_events(), request processing stalls until an unrelated wakeup arrives. The fix uses atomic_cmpxchg instead of atomic_sub_return to guarantee both the count v and poll_refs are 0 and no wakeups are missed.
- CVE-2026-99262Unknown
In io_uring/timeout, an IORING_OP_TIMEOUT run by io-wq due to IOSQE_ASYNC has the same problem as poll, futex, and waitid. io_wq_submit_work() checks IO_WQ_WORK_CANCEL only once before issuing the request; a cancel in between flags the work, gets -EALREADY, and searches ->timeout_list in vain while the worker adds the request and starts the timer. Nobody checks the flag again and the timeout runs its course, and at ring exit a task can get stuck for the full duration. The fix checks the flag under ->timeout_lock and fails the request if set.
- CVE-2026-99261Unknown
In the drm/amdgpu driver, reservation fence slot allocation for eviction of userq per-vm BOs has been corrected. The fix addresses both the move overflow and the eviction fence add for these buffers.
Original NVD description (English source)
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 ]
Vulnerability data from NVD (NIST) · CISA KEV · EPSS