CVE-2026-89634
Published: September 15, 2026Last modified: September 28, 2026
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.
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score | 9.1 |
| Attack Vector | NETWORK |
| Attack complexity | LOW |
| Privileges required | NONE |
| User interaction | NONE |
| Scope | UNCHANGED |
| Confidentiality | HIGH |
| Integrity impact | NONE |
| Availability impact | HIGH |
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H |
Status
| Product | Release | Package | Status |
|---|---|---|---|
| Alpaquita Linux | 23 LTS | linux-lts | Vulnerable (6.1.182-r0) |
| 25 LTS | linux-lts | Fixed (6.12.111-r0) | |
| Stream | linux-lts | Fixed (6.18.53-r0) |
References
- https://git.kernel.org/stable/c/1f824f61d1df52392eaf0b74dfa5659d724fde30
- https://git.kernel.org/stable/c/2b4a25baa0b936fef6915c0459925077b324ecaf
- https://git.kernel.org/stable/c/62656b024efc21c3230eade1a847f25871c3d2bb
- https://git.kernel.org/stable/c/62a3025983c8c735a3c6fc85a59316f31b59af07
- https://git.kernel.org/stable/c/657372ba6ea50b4474d2a6a610097eae8cd1f3e9
- https://git.kernel.org/stable/c/b89d678f9eafcf8d74885983166ba26b40a04ea0