Answer in brief
CVE-2026-68100 records a Unknown severity vulnerability in ksmbd: validate num_subauth when copying ACE in set_ntacl_dacl. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. 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). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <e31fada5143784bc05c7ae44c79eed9b7a2e147e || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <fb3dc8e6da46a1ccad1956cda57de29d9b3033e0 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <b6d3cc6a524416dfdb2b47e4bba2e7e20011d056 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <5acbd3012fd4a7ccfebd91ea6f784120084eb897 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <47f0b34f6bc98ed85bfdc293e8f3e432ec24958d || >=0 <6.6.148 || >=0 <6.12.101 || >=0 <6.18.42 || >=0 <7.1.6 | e31fada5143784bc05c7ae44c79eed9b7a2e147e, fb3dc8e6da46a1ccad1956cda57de29d9b3033e0, b6d3cc6a524416dfdb2b47e4bba2e7e20011d056, 5acbd3012fd4a7ccfebd91ea6f784120084eb897, 47f0b34f6bc98ed85bfdc293e8f3e432ec24958d, 6.6.148, 6.12.101, 6.18.42, 7.1.6 |
Published upstream
Aug 10, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 10, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 10, 2026
In the Linux kernel, the following vulnerability has been resolved: ksmbd: validate num_subauth when copying ACE in set_ntacl_dacl set_ntacl_dacl() copies each ACE from the attacker-controlled stored security descriptor verbatim into the response DACL without checking sid.num_subauth. The ACE bytes (including an unchecked num_subauth) originate from an authenticated SMB2_SET_INFO(SecInfo=DACL) that is stored raw via ksmbd_vfs_set_sd_xattr(); parse_dacl() rejects a bad ACE with `break` rather than an error, so parse_sec_desc() still returns success and the malformed SD reaches the xattr intact. On a subsequent SMB2_QUERY_INFO(SecInfo=DACL) for an inode carrying a POSIX access ACL, build_sec_desc() -> set_ntacl_dacl() -> set_posix_acl_entries_dacl() walks the copied ACEs and reads ntace->sid.sub_auth[ntace->sid.num_subauth - 1] with num_subauth taken straight from the stored SD. Since sub_auth[] is fixed at SID_MAX_SUB_AUTHORITIES (15), a crafted num_subauth (e.g. 255) drives an out-of-bounds heap read of ~1 KB with an offset fully controlled by an authenticated client. The sibling functions already gate this field: parse_dacl() -- num_subauth == 0 || > SID_MAX_SUB_AUTHORITIES parse_sid() -- num_subauth > SID_MAX_SUB_AUTHORITIES smb_copy_sid() -- min_t(u8, num_subauth, SID_MAX_SUB_AUTHORITIES) set_ntacl_dacl() is the lone inconsistent path that omits the check. Add the same num_subauth validation in set_ntacl_dacl() before copying the ACE, matching the gate already enforced by parse_dacl().
Quoted source text, attributed separately from HOL analysis.
Answer in brief
CVE-2026-68100 records a Unknown severity vulnerability in ksmbd: validate num_subauth when copying ACE in set_ntacl_dacl. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. 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). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <e31fada5143784bc05c7ae44c79eed9b7a2e147e || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <fb3dc8e6da46a1ccad1956cda57de29d9b3033e0 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <b6d3cc6a524416dfdb2b47e4bba2e7e20011d056 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <5acbd3012fd4a7ccfebd91ea6f784120084eb897 || >=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <47f0b34f6bc98ed85bfdc293e8f3e432ec24958d || >=0 <6.6.148 || >=0 <6.12.101 || >=0 <6.18.42 || >=0 <7.1.6 | e31fada5143784bc05c7ae44c79eed9b7a2e147e, fb3dc8e6da46a1ccad1956cda57de29d9b3033e0, b6d3cc6a524416dfdb2b47e4bba2e7e20011d056, 5acbd3012fd4a7ccfebd91ea6f784120084eb897, 47f0b34f6bc98ed85bfdc293e8f3e432ec24958d, 6.6.148, 6.12.101, 6.18.42, 7.1.6 |
Published upstream
Aug 10, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 10, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 10, 2026
In the Linux kernel, the following vulnerability has been resolved: ksmbd: validate num_subauth when copying ACE in set_ntacl_dacl set_ntacl_dacl() copies each ACE from the attacker-controlled stored security descriptor verbatim into the response DACL without checking sid.num_subauth. The ACE bytes (including an unchecked num_subauth) originate from an authenticated SMB2_SET_INFO(SecInfo=DACL) that is stored raw via ksmbd_vfs_set_sd_xattr(); parse_dacl() rejects a bad ACE with `break` rather than an error, so parse_sec_desc() still returns success and the malformed SD reaches the xattr intact. On a subsequent SMB2_QUERY_INFO(SecInfo=DACL) for an inode carrying a POSIX access ACL, build_sec_desc() -> set_ntacl_dacl() -> set_posix_acl_entries_dacl() walks the copied ACEs and reads ntace->sid.sub_auth[ntace->sid.num_subauth - 1] with num_subauth taken straight from the stored SD. Since sub_auth[] is fixed at SID_MAX_SUB_AUTHORITIES (15), a crafted num_subauth (e.g. 255) drives an out-of-bounds heap read of ~1 KB with an offset fully controlled by an authenticated client. The sibling functions already gate this field: parse_dacl() -- num_subauth == 0 || > SID_MAX_SUB_AUTHORITIES parse_sid() -- num_subauth > SID_MAX_SUB_AUTHORITIES smb_copy_sid() -- min_t(u8, num_subauth, SID_MAX_SUB_AUTHORITIES) set_ntacl_dacl() is the lone inconsistent path that omits the check. Add the same num_subauth validation in set_ntacl_dacl() before copying the ACE, matching the gate already enforced by parse_dacl().
Quoted source text, attributed separately from HOL analysis.