CVE-2026-89634

smb: client: fix ALIGN() overflow in symlink_data() error context loop

State: Published
Severity: 9.1 Critical
Published: Sep 11, 2026
Updated: Oct 19, 2026
Reserved: Sep 11, 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.

Scores

CVSS	Score	Vector	Source
3.1	9.1 Critical	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H	Linux

Weaknesses

The record names no weakness.

Affected Products

Product	Versions
LinuxLinux	76894f3e2f71177747b8b4763fb180e800279585 to before 2b4a25baa0b936fef6915c0459925077b324ecafAffected 76894f3e2f71177747b8b4763fb180e800279585 to before b89d678f9eafcf8d74885983166ba26b40a04ea0Affected 76894f3e2f71177747b8b4763fb180e800279585 to before 657372ba6ea50b4474d2a6a610097eae8cd1f3e9Affected 76894f3e2f71177747b8b4763fb180e800279585 to before 1f824f61d1df52392eaf0b74dfa5659d724fde30Affected 76894f3e2f71177747b8b4763fb180e800279585 to before 62a3025983c8c735a3c6fc85a59316f31b59af07Affected 76894f3e2f71177747b8b4763fb180e800279585 to before 62656b024efc21c3230eade1a847f25871c3d2bbAffected 2d046892a493d9760c35fdaefc3017f27f91b621Affected 6.0.16 to before 6.1Affected
LinuxLinux	6.1Affected before 6.1Not affected 6.1.188 through 6.1.Not affected 6.6.157 through 6.6.Not affected 6.12.109 through 6.12.Not affected 6.18.50 through 6.18.Not affected 7.2.4 through 7.2.*Not affected 7.3 and laterNot affected

Product

Versions

LinuxLinux

76894f3e2f71177747b8b4763fb180e800279585 to before 2b4a25baa0b936fef6915c0459925077b324ecafAffected
76894f3e2f71177747b8b4763fb180e800279585 to before b89d678f9eafcf8d74885983166ba26b40a04ea0Affected
76894f3e2f71177747b8b4763fb180e800279585 to before 657372ba6ea50b4474d2a6a610097eae8cd1f3e9Affected
76894f3e2f71177747b8b4763fb180e800279585 to before 1f824f61d1df52392eaf0b74dfa5659d724fde30Affected
76894f3e2f71177747b8b4763fb180e800279585 to before 62a3025983c8c735a3c6fc85a59316f31b59af07Affected
76894f3e2f71177747b8b4763fb180e800279585 to before 62656b024efc21c3230eade1a847f25871c3d2bbAffected
2d046892a493d9760c35fdaefc3017f27f91b621Affected
6.0.16 to before 6.1Affected

LinuxLinux

6.1Affected
before 6.1Not affected
6.1.188 through 6.1.*Not affected
6.6.157 through 6.6.*Not affected
6.12.109 through 6.12.*Not affected
6.18.50 through 6.18.*Not affected
7.2.4 through 7.2.*Not affected
7.3 and laterNot affected

References

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