{"id":"DEBIAN-CVE-2026-64578","details":"In the Linux kernel, the following vulnerability has been resolved:  ksmbd: validate compound request size before reading StructureSize2  When ksmbd validates a compound (chained) SMB2 request, ksmbd_smb2_check_message() reads pdu-\u003eStructureSize2 without first checking that the compound element is large enough to contain it. StructureSize2 is a 2-byte field at offset 64 (__SMB2_HEADER_STRUCTURE_SIZE) from the start of each element.  The compound-walking logic only guarantees that a full 64-byte SMB2 header is present for the trailing element: when NextCommand is 0, len is reduced to the number of bytes remaining after next_smb2_rcv_hdr_off. A remote client can craft a compound request whose last element has exactly 64 bytes, so the 2-byte StructureSize2 read at offset 64 extends one byte past the receive buffer, producing a slab-out-of-bounds read.    BUG: KASAN: slab-out-of-bounds in ksmbd_smb2_check_message (fs/smb/server/smb2misc.c:402)   Read of size 2 at addr ffff888012ae31ac by task kworker/0:1/14   The buggy address is located 172 bytes inside of allocated 173-byte region   Workqueue: ksmbd-io handle_ksmbd_work   Call Trace:    ...    kasan_report (mm/kasan/report.c:595)    ksmbd_smb2_check_message (fs/smb/server/smb2misc.c:402)    handle_ksmbd_work (fs/smb/server/server.c:119)    process_one_work (kernel/workqueue.c:3314)    worker_thread (kernel/workqueue.c:3397)    kthread (kernel/kthread.c:436)    ret_from_fork (arch/x86/kernel/process.c:158)    ret_from_fork_asm (arch/x86/entry/entry_64.S:245)  Reject any compound element that is too small to hold StructureSize2 before dereferencing it.","modified":"2026-09-14T17:03:45.805824209Z","published":"2026-08-05T08:16:37.760Z","upstream":["CVE-2026-64578"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2026-64578"}],"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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