SB20260424253 - Incorrect Calculation of Buffer Size in Linux kernel smb server
Published: April 24, 2026
Security Bulletin ID
SB20260424253
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Remote access
Highest impact
Denial of service
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 vulnerability.
1) Incorrect Calculation of Buffer Size (CVE-ID: CVE-2026-31478)
CWE-ID: CWE-131 - Incorrect Calculation of Buffer Size
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
The vulnerability allows a remote user to cause a denial of service.
The vulnerability exists due to improper buffer size calculation in smb2_calc_max_out_buf_len() when handling SMB2 compound read responses. A remote user can send a specially crafted SMB request to cause a denial of service.
Remediation
Install update from vendor's website.
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