CVE-2026-64578 Affecting linux-6.12 package, versions <6.12.101-1~deb12u1
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-ECHOLATEST-LINUX612-18912426
- published18 Aug 2026
- disclosed5 Aug 2026
Introduced: 5 Aug 2026
CVE-2026-64578 (opens in a new tab)How to fix?
Upgrade Echo:latest linux-6.12 to version 6.12.101-1~deb12u1 or higher.
NVD Description
Note: Versions mentioned in the description apply only to the upstream linux-6.12 package and not the linux-6.12 package as distributed by Echo.
See How to fix? for Echo:latest relevant fixed versions and status.
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->StructureSize2 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.
References
- https://advisory.echohq.com/cve/CVE-2026-64578
- https://git.kernel.org/stable/c/15b38176fd1530372905c602fde51fe89ec8c877
- https://git.kernel.org/stable/c/2c307126ed8e7adddab82b8e31d962d3a2156ab1
- https://git.kernel.org/stable/c/ea128f06d2fb2186f0cac0c9f3e953e4d1f5c29a
- https://git.kernel.org/stable/c/f0e337e7db67cc1c832958bbb6c4026bdceacfdb
- https://git.kernel.org/stable/c/f7550a91ab211726f59cb137523b7a9eae1ac6eb
- https://git.kernel.org/stable/c/1b6740525f5af90868d557c31b496ae689c8c549
- https://git.kernel.org/stable/c/415d0fff0451ad7ad4caa910f2bb0f562f0fd60f