Critical severity · published Apr 22, 2026
CVE-2026-31478
ksmbd: replace hardcoded hdr2_len with offsetof() in smb2_calc_max_out_buf_len()
9.8
CVSS
0.5%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 43% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
KE
Kernel · Linux
5.15.145 before 5.15.203; 6.1.71 before 6.1.168; 6.6.1 before 6.6.131; 6.7 before 6.12.80; 6.13 before 6.18.21; 6.19 before 6.19.11; +8 more · source: NVD
LI
Linux · Linux
f2283680a80571ca82d710bc6ecd8f8beac67d63 before 70b4c414889492c522b6e4331562360f49be2361; 9f297df20d93411c0b4ddad7f88ba04a7cd36e77 before 9a7166f0ef8cbb7bb48dd05e2471d995566003f5; e2b76ab8b5c9327ab2dae6da05d0752eb2f4771d before c3a89e3ec1ccf64fa6a34e391e1581ebbcba8683; e2b76ab8b5c9327ab2dae6da05d0752eb2f4771d before 6aef1765d6807e0f027cd87f6ac973eb0879a46d; e2b76ab8b5c9327ab2dae6da05d0752eb2f4771d before 80824c7e527b70cf9039534e60aff592e8f209d1; e2b76ab8b5c9327ab2dae6da05d0752eb2f4771d before 4cb537ae4f37d7d0f617815ed4bed7173fb50861; +4 more · source: vendor