Answer in brief
CVE-2026-31611 records a High severity (CVSS 8.6) vulnerability in ksmbd: require 3 sub-authorities before reading sub_auth[2]. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic), Siemens/SIMATIC S7-1500 TM MFP - GNU/Linux subsystem (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 8.6. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic), Siemens/SIMATIC S7-1500 TM MFP - GNU/Linux subsystem (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <cf2148b880fb7c0fcd727202dbc4fd5d6998b9c2 || >=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <b5b5d5936a50497fb151c0b122899a6894721c2b || >=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <08f9e6d899b5c834bbcc239eae1bed58d9b15d2c || >=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <d2454f4a002d08560a60f214f392e6491cf11560 || >=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <46bbcd3ebfb3549c8da1838fc4493e79bd3241e7 || >=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <9401f86a224f37b50e6a3ccf1d46a70d5ef8af0a || >=e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 <53370cf9090777774e07fd9a8ebce67c6cc333ab | cf2148b880fb7c0fcd727202dbc4fd5d6998b9c2, b5b5d5936a50497fb151c0b122899a6894721c2b, 08f9e6d899b5c834bbcc239eae1bed58d9b15d2c, d2454f4a002d08560a60f214f392e6491cf11560, 46bbcd3ebfb3549c8da1838fc4493e79bd3241e7, 9401f86a224f37b50e6a3ccf1d46a70d5ef8af0a, 53370cf9090777774e07fd9a8ebce67c6cc333ab |
| Linux/Linuxgeneric | 5.15 | Not reported |
| Siemens/SIMATIC S7-1500 TM MFP - GNU/Linux subsystemgeneric | >=0 <* | * |
Published upstream
Apr 24, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 15, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Oct 15, 2026
In the Linux kernel, the following vulnerability has been resolved: ksmbd: require 3 sub-authorities before reading sub_auth[2] parse_dacl() compares each ACE SID against sid_unix_NFS_mode and on match reads sid.sub_auth[2] as the file mode. If sid_unix_NFS_mode is the prefix S-1-5-88-3 with num_subauth = 2 then compare_sids() compares only min(num_subauth, 2) sub-authorities so a client SID with num_subauth = 2 and sub_auth = {88, 3} will match. If num_subauth = 2 and the ACE is placed at the very end of the security descriptor, sub_auth[2] will be 4 bytes past end_of_acl. The out-of-band bytes will then be masked to the low 9 bits and applied as the file's POSIX mode, probably not something that is good to have happen. Fix this up by forcing the SID to actually carry a third sub-authority before reading it at all.
Quoted source text, attributed separately from HOL analysis.