Critical severity · published Jul 25, 2026
CVE-2026-64391
ksmbd: use opener credentials for ADS I/O
9.8
CVSS
0.5%
EPSS
No
On KEV
Description
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: use opener credentials for ADS I/O
Alternate data streams are stored as xattrs. Unlike regular file I/O,
their read and write paths therefore call VFS xattr helpers which recheck
inode permissions and LSM policy using the current task credentials.
Run ADS I/O with the credentials captured when the SMB handle was opened.
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 39% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
KE
Kernel · Linux
5.15 before 6.12.96; 6.13 before 6.18.39; 6.19 before 7.1.4 · source: NVD
LI
Linux · Linux
f44158485826c076335d6860d35872271a83791d before 2ad5509dd576ae16d252d4698daf03002f9e0234; f44158485826c076335d6860d35872271a83791d before a8f5d39971bbad9340d49cd41b0e2da9452a649d; f44158485826c076335d6860d35872271a83791d before 2b4592cea214683de0f2ce6f8c22c097fb0ea1ab; f44158485826c076335d6860d35872271a83791d before 52a56cf53ec834c44ac1b4d16d585f26613ee5ce; f44158485826c076335d6860d35872271a83791d before baa5e094886fffa7e6272edcb5e08be5ce28262c; 5.15 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-64391
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-64391
git.kernel.org
https://git.kernel.org/stable/c/2ad5509dd576ae16d252d4698daf03002f9e0234
Patch
https://git.kernel.org/stable/c/2b4592cea214683de0f2ce6f8c22c097fb0ea1ab
Patch
https://git.kernel.org/stable/c/52a56cf53ec834c44ac1b4d16d585f26613ee5ce
Patch
https://git.kernel.org/stable/c/a8f5d39971bbad9340d49cd41b0e2da9452a649d
Patch
https://git.kernel.org/stable/c/baa5e094886fffa7e6272edcb5e08be5ce28262c
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