Answer in brief
CVE-2026-63909 records a Unknown severity vulnerability in ksmbd: OOB read regression in smb_check_perm_dacl() ACE-walk loops. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), 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.
Answer in brief
CVE-2026-63909 records a Unknown severity vulnerability in ksmbd: OOB read regression in smb_check_perm_dacl() ACE-walk loops. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), 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), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=282cbbb476b9f35793452bc461934af4c7eca169 <5500ba1d410aed1eded3eb04a76b10cfb4409334 || >=f20adc4ef7428bc485ee83fd1a592252fb87718b <f6324b4240cf0b26a84c33f68a1222d727ff4af2 || >=325d4ac11f526cb8964cff14548ccf02d8c756d8 <0fe08c5776a798f46df1fd74b331be26bdd644d6 || >=95e5aa3c3261da8c95b27d7aecf8ee39b9f86a4c <d333af32e4451285e427f2d9c29de3a39f6f6d48 || >=90089584b2e25c4510b7b987387b4405f0673ece <94215d55b09445993929f4fc966061d61de74929 || >=151b1799861fde38087c08f613abc2843ef597b0 <4f7c131d2bdd7cd64b96f60d10be5ea72253f520 || >=d07b26f39246a82399661936dd0c853983cfade7 <0e60dafe97eca61721f3db456f97d97a80c6c8ae | 5500ba1d410aed1eded3eb04a76b10cfb4409334, f6324b4240cf0b26a84c33f68a1222d727ff4af2, 0fe08c5776a798f46df1fd74b331be26bdd644d6, d333af32e4451285e427f2d9c29de3a39f6f6d48, 94215d55b09445993929f4fc966061d61de74929, 4f7c131d2bdd7cd64b96f60d10be5ea72253f520, 0e60dafe97eca61721f3db456f97d97a80c6c8ae |
| Linux/Linuxgeneric | >=6.6.140 <6.6.143 || >=6.12.84 <6.12.93 || >=6.18.25 <6.18.35 || >=7.0.2 <7.0.12 | 6.6.143, 6.12.93, 6.18.35, 7.0.12 |
Published upstream
Jul 19, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 5, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 5, 2026
In the Linux kernel, the following vulnerability has been resolved: ksmbd: OOB read regression in smb_check_perm_dacl() ACE-walk loops Commit d07b26f39246 ("ksmbd: require minimum ACE size in smb_check_perm_dacl()") introduced a transposed bounds check: if (offsetof(struct smb_ace, sid) + aces_size < CIFS_SID_BASE_SIZE) Since offsetof(..sid) is 8 and CIFS_SID_BASE_SIZE is 8, this evaluates to `aces_size < 0`. Because `aces_size` is always non-negative, this check becomes dead code and never breaks the loop. Worse, that commit removed the old 4-byte guard, meaning the loop now reads `ace->size` (offset 2) even when `aces_size` is 0-3 bytes. This re-opens a 2-byte heap out-of-bounds (OOB) read past the pntsd allocation during subsequent SMB2_CREATE operations. Fix this by properly transposing the comparison to require at least 16 bytes (8-byte offset + 8-byte SID base), matching the correct form used in smb_inherit_dacl().
Quoted source text, attributed separately from HOL analysis.
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), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=282cbbb476b9f35793452bc461934af4c7eca169 <5500ba1d410aed1eded3eb04a76b10cfb4409334 || >=f20adc4ef7428bc485ee83fd1a592252fb87718b <f6324b4240cf0b26a84c33f68a1222d727ff4af2 || >=325d4ac11f526cb8964cff14548ccf02d8c756d8 <0fe08c5776a798f46df1fd74b331be26bdd644d6 || >=95e5aa3c3261da8c95b27d7aecf8ee39b9f86a4c <d333af32e4451285e427f2d9c29de3a39f6f6d48 || >=90089584b2e25c4510b7b987387b4405f0673ece <94215d55b09445993929f4fc966061d61de74929 || >=151b1799861fde38087c08f613abc2843ef597b0 <4f7c131d2bdd7cd64b96f60d10be5ea72253f520 || >=d07b26f39246a82399661936dd0c853983cfade7 <0e60dafe97eca61721f3db456f97d97a80c6c8ae | 5500ba1d410aed1eded3eb04a76b10cfb4409334, f6324b4240cf0b26a84c33f68a1222d727ff4af2, 0fe08c5776a798f46df1fd74b331be26bdd644d6, d333af32e4451285e427f2d9c29de3a39f6f6d48, 94215d55b09445993929f4fc966061d61de74929, 4f7c131d2bdd7cd64b96f60d10be5ea72253f520, 0e60dafe97eca61721f3db456f97d97a80c6c8ae |
| Linux/Linuxgeneric | >=6.6.140 <6.6.143 || >=6.12.84 <6.12.93 || >=6.18.25 <6.18.35 || >=7.0.2 <7.0.12 | 6.6.143, 6.12.93, 6.18.35, 7.0.12 |
Published upstream
Jul 19, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 5, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 5, 2026
In the Linux kernel, the following vulnerability has been resolved: ksmbd: OOB read regression in smb_check_perm_dacl() ACE-walk loops Commit d07b26f39246 ("ksmbd: require minimum ACE size in smb_check_perm_dacl()") introduced a transposed bounds check: if (offsetof(struct smb_ace, sid) + aces_size < CIFS_SID_BASE_SIZE) Since offsetof(..sid) is 8 and CIFS_SID_BASE_SIZE is 8, this evaluates to `aces_size < 0`. Because `aces_size` is always non-negative, this check becomes dead code and never breaks the loop. Worse, that commit removed the old 4-byte guard, meaning the loop now reads `ace->size` (offset 2) even when `aces_size` is 0-3 bytes. This re-opens a 2-byte heap out-of-bounds (OOB) read past the pntsd allocation during subsequent SMB2_CREATE operations. Fix this by properly transposing the comparison to require at least 16 bytes (8-byte offset + 8-byte SID base), matching the correct form used in smb_inherit_dacl().
Quoted source text, attributed separately from HOL analysis.