{"id":"DEBIAN-CVE-2026-68082","details":"In the Linux kernel, the following vulnerability has been resolved:  libceph: fix two unsafe bare decodes in decode_lockers()  decode_lockers() in cls_lock_client.c contains two bare decode operations that allow a malicious or compromised OSD to trigger slab-out-of-bounds reads:  1. ceph_decode_32(p) at the num_lockers field has no preceding bounds    check. ceph_start_decoding() accepts struct_len=0 as valid -- the    internal ceph_decode_need(p, end, 0, bad) always passes -- so when an    OSD sends struct_len=0, ceph_start_decoding() returns success with    p == end. The immediately following bare ceph_decode_32(p) then reads    4 bytes past the validated buffer boundary. The garbage value is    passed directly to kzalloc_objs() as the locker count.     The sibling function decode_watchers() in osd_client.c already uses    ceph_decode_32_safe() after its own ceph_start_decoding() call.    decode_lockers() was the only site using the bare variant.  2. ceph_decode_8(p) after the decode_locker() loop has no preceding    bounds check. If an OSD crafts num_lockers such that the loop    advances p exactly to end, the subsequent bare ceph_decode_8(p) reads    one byte past the validated buffer boundary. The result is passed    directly into *type, which is used as a lock type discriminator by    callers, giving an OSD-controlled one-byte OOB read with direct    influence over the lock type field.  Fix both by replacing bare operations with their safe variants:   ceph_decode_32(p) -\u003e ceph_decode_32_safe(p, end, *num_lockers,                                            err_inval)   ceph_decode_8(p)  -\u003e ceph_decode_8_safe(p, end, *type,                                           err_free_lockers)  The goto targets differ intentionally:   err_inval: is a new label returning -EINVAL directly. It is used for   the pre-allocation failure path where *lockers is not yet allocated   and must not be passed to ceph_free_lockers().    err_free_lockers: is the existing label. It is used for the   post-allocation failure path where *lockers is allocated and must   be freed.  ret is set to -EINVAL before ceph_decode_8_safe() so that err_free_lockers returns the correct error code on bounds violation. Without this, err_free_lockers would return a stale ret value (0 from the successful decode_locker() loop), silently swallowing the error.  -EINVAL is correct for both failure paths. The data received from the OSD is structurally malformed. -ENOMEM would misrepresent the failure class to callers and to stable@ backporters triaging error paths.  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).  [ idryomov: trim changelog, formatting ]","modified":"2026-09-19T22:02:22.696928136Z","published":"2026-08-08T10:16:55.377Z","upstream":["CVE-2026-68082"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2026-68082"}],"affected":[{"package":{"name":"linux","ecosystem":"Debian:12","purl":"pkg:deb/debian/linux?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.1.187-1"}]}],"versions":["6.1.106-1","6.1.106-2","6.1.106-3","6.1.112-1","6.1.115-1","6.1.119-1","6.1.123-1","6.1.124-1","6.1.128-1","6.1.129-1","6.1.133-1","6.1.135-1","6.1.137-1","6.1.139-1","6.1.140-1","6.1.147-1","6.1.148-1","6.1.153-1","6.1.158-1","6.1.159-1","6.1.162-1","6.1.164-1","6.1.170-1","6.1.170-2","6.1.170-3","6.1.172-1","6.1.174-1","6.1.176-1","6.1.177-1","6.1.180-1","6.1.27-1","6.1.37-1","6.1.38-1","6.1.38-2","6.1.38-2~bpo11+1","6.1.38-3","6.1.38-4","6.1.38-4~bpo11+1","6.1.52-1","6.1.55-1","6.1.55-1~bpo11+1","6.1.64-1","6.1.66-1","6.1.67-1","6.1.69-1","6.1.69-1~bpo11+1","6.1.76-1","6.1.76-1~bpo11+1","6.1.82-1","6.1.85-1","6.1.90-1","6.1.90-1~bpo11+1","6.1.94-1","6.1.94-1~bpo11+1","6.1.98-1","6.1.99-1"],"ecosystem_specific":{"urgency":"not 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