CVE-2026-89634

Summary

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.

Affected Software

VendorProductVersion RangeStatus
LinuxLinux76894f3e2f71177747b8b4763fb180e800279585 < 657372ba6ea50b4474d2a6a610097eae8cd1f3e9affected
LinuxLinux76894f3e2f71177747b8b4763fb180e800279585 < 1f824f61d1df52392eaf0b74dfa5659d724fde30affected
LinuxLinux76894f3e2f71177747b8b4763fb180e800279585 < 62a3025983c8c735a3c6fc85a59316f31b59af07affected
LinuxLinux76894f3e2f71177747b8b4763fb180e800279585 < 62656b024efc21c3230eade1a847f25871c3d2bbaffected
LinuxLinux2d046892a493d9760c35fdaefc3017f27f91b621affected
LinuxLinux6.0.16 < 6.1affected
LinuxLinux6.1affected
LinuxLinux0 < 6.1unaffected
LinuxLinux6.12.109 <= 6.12.*unaffected
LinuxLinux6.18.50 <= 6.18.*unaffected
LinuxLinux7.2.4 <= 7.2.*unaffected
LinuxLinux7.3-rc1 <= *unaffected

Weaknesses

References