CVE-2026-31478
Description
In the Linux kernel, the following vulnerability has been resolved: ksmbd: replace hardcoded hdr2_len with offsetof() in smb2_calc_max_out_buf_len() After this commit (e2b76ab8b5c9 "ksmbd: add support for read compound"), response buffer management was changed to use dynamic iov array. In the new design, smb2_calc_max_out_buf_len() expects the second argument (hdr2_len) to be the offset of ->Buffer field in the response structure, not a hardcoded magic number. Fix the remaining call sites to use the correct offsetof() value.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
Vendor advisory: debian — https://security-tracker.debian.org/tracker/CVE-2026-31478
Vendor advisory: suse — https://www.suse.com/security/cve/CVE-2026-31478.html
Vendor advisory: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 — https://git.kernel.org/stable/c/c3a89e3ec1ccf64fa6a34e391e1581ebbcba8683
Vendor advisory: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 — https://git.kernel.org/stable/c/9a7166f0ef8cbb7bb48dd05e2471d995566003f5
Vendor advisory: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 — https://git.kernel.org/stable/c/80824c7e527b70cf9039534e60aff592e8f209d1
Vendor advisory: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 — https://git.kernel.org/stable/c/70b4c414889492c522b6e4331562360f49be2361
Vendor advisory: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 — https://git.kernel.org/stable/c/6aef1765d6807e0f027cd87f6ac973eb0879a46d
Vendor advisory: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 — https://git.kernel.org/stable/c/4cb537ae4f37d7d0f617815ed4bed7173fb50861
Vendor advisory: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 — https://git.kernel.org/stable/c/0e55f63dd08f09651d39e1b709a91705a8a0ddcb
OS impact
| OS | Version | Status | Fixed in |
|---|---|---|---|
| sles | affected | | |
| debian | bookworm | fixed | 6.1.170-1 |
| debian | bullseye | fixed | 0 |
| debian | forky | fixed | 6.19.11-1 |
| debian | sid | fixed | 6.19.11-1 |
| debian | trixie | fixed | 6.12.85-1 |
| linux-kernel | affected | 5.15.203 | |
| linux-kernel | 6.6 | affected | |
| linux-kernel | 7.0 | affected | |
References
- https://git.kernel.org/stable/c/0e55f63dd08f09651d39e1b709a91705a8a0ddcb
- https://git.kernel.org/stable/c/4cb537ae4f37d7d0f617815ed4bed7173fb50861
- https://git.kernel.org/stable/c/6aef1765d6807e0f027cd87f6ac973eb0879a46d
- https://git.kernel.org/stable/c/70b4c414889492c522b6e4331562360f49be2361
- https://git.kernel.org/stable/c/80824c7e527b70cf9039534e60aff592e8f209d1
- https://git.kernel.org/stable/c/9a7166f0ef8cbb7bb48dd05e2471d995566003f5
- https://git.kernel.org/stable/c/c3a89e3ec1ccf64fa6a34e391e1581ebbcba8683
- https://www.suse.com/security/cve/CVE-2026-31478.html
- https://security-tracker.debian.org/tracker/CVE-2026-31478
Verify integrity in audit chain (admin only). AS-IS.