CVEvulnerability
CVE-2026-89634
9.1 CRITICAL
Official page ↗
- Status
- Received
- Published
- 2026-09-11
- Last modified
- 2026-10-19
- Assigner
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
- CVSS 3.1 (416baaa9-dc9f-4396-8d5f-8c081fb06d67)
- 9.1 CRITICAL — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
Description
In the Linux kernel, the following vulnerability has been resolved:
smb: client: fix ALIGN() overflow in symlink_data() error context loop
The check added by commit 7d9a7f1f96cd ("smb/client: fix possible
infinite loop and oob read in symlink_data()") compared the post-ALIGN
length against the remaining buffer, but ALIGN() itself can overflow:
for ErrorDataLength near UINT32_MAX (e.g. 0xFFFFFFF9), ALIGN(x, 8)
wraps to 0, so the subsequent bounds check passes, and the loop
advances by zero bytes leaving 'p' pointing into stale data.
Fix by checking the raw ErrorDataLength against the remaining space
before applying ALIGN(), then checking again after. Since raw_len is
bounded by the buffer, raw_len + 7 cannot overflow, so the second check
is an exact post-alignment bounds guard.
References
- https://git.kernel.org/stable/c/1f824f61d1df52392eaf0b74dfa5659d724fde30 git.kernel.org
- https://git.kernel.org/stable/c/2b4a25baa0b936fef6915c0459925077b324ecaf git.kernel.org
- https://git.kernel.org/stable/c/62656b024efc21c3230eade1a847f25871c3d2bb git.kernel.org
- https://git.kernel.org/stable/c/62a3025983c8c735a3c6fc85a59316f31b59af07 git.kernel.org
- https://git.kernel.org/stable/c/657372ba6ea50b4474d2a6a610097eae8cd1f3e9 git.kernel.org
- https://git.kernel.org/stable/c/b89d678f9eafcf8d74885983166ba26b40a04ea0 git.kernel.org