CVE-2026-31478

moderate-risk
Published 2026-04-22

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.

Do I need to act?

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0.03% chance of exploitation
EPSS score — low exploit probability
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Not on CISA KEV list
No confirmed active exploitation reported to CISA
?
Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
9
CVSS 9.8/10 Critical
NETWORK / LOW complexity

Affected Products (9)

Affected Vendors

Linux

References (7)

Patch https://git.kernel.org/stable/c/0e55f63dd08f09651d39e1b709a91705a8a0ddcb
Patch https://git.kernel.org/stable/c/4cb537ae4f37d7d0f617815ed4bed7173fb50861
Patch https://git.kernel.org/stable/c/6aef1765d6807e0f027cd87f6ac973eb0879a46d
Patch https://git.kernel.org/stable/c/70b4c414889492c522b6e4331562360f49be2361
Patch https://git.kernel.org/stable/c/80824c7e527b70cf9039534e60aff592e8f209d1
Patch https://git.kernel.org/stable/c/9a7166f0ef8cbb7bb48dd05e2471d995566003f5
Patch https://git.kernel.org/stable/c/c3a89e3ec1ccf64fa6a34e391e1581ebbcba8683
47
/ 100
moderate-risk
Severity 32/34 · Critical
Exploitability 0/34 · Minimal
Exposure 15/34 · Moderate