CVE-2026-64388smb/client: fix chown/chgrp with SMB3 POSIX Extensions
- 7.8HighCVSS base score
- 0.13%Exploitation in 30 daysEPSS · top 97% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
In the Linux kernel, the following vulnerability has been resolved: smb/client: fix chown/chgrp with SMB3 POSIX Extensions Ownership (chown) and group (chgrp) modifications were being ignored when mounting with SMB3 POSIX Extensions unless CIFS_MOUNT_CIFS_ACL or CIFS_MOUNT_MODE_FROM_SID were also explicitly set. Fix this by checking for posix_extensions in cifs_setattr_nounix() when updating UID and GID, ensuring that id_mode_to_cifs_acl() is called to map and set the ownership/group information on the server.
Timeline
ID reserved
By Linux
- 6 days later
· 6 days later
Published
- 3 months later
· 3 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| LinuxCNA (assigner) | 3.1 | High7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| NVDNVD · Modified | 3.1 | High7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 0.13% · top 97% of all CVEs (15 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: total
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.8.
Affected products
- affected b326614ea2159ea5c835d320f261d05d080cd201 – < c0fe1118a1471d459f76c3e70ff2abbf784ce6bf
- affected b326614ea2159ea5c835d320f261d05d080cd201 – < 6825a45f6b8ef76b0ee32649ec3d6e39ca143a18
- affected b326614ea2159ea5c835d320f261d05d080cd201 – < 27ead8c5418af6bfab711079fecb9414d78d4cae
- affected b326614ea2159ea5c835d320f261d05d080cd201 – < 3eaec47518e126e6dcd1a48521d740278073f0ec
- affected b326614ea2159ea5c835d320f261d05d080cd201 – < 550cfb8a81181331d4d0f76ab75ee58a0bf41e3e
- affected b326614ea2159ea5c835d320f261d05d080cd201 – < 760ef2c579c2609cf17fb1cd5392f64d42d43d33
- affected 4.18
- unaffected < 4.18
- unaffected 6.1.191 – ≤ 6.1.*
- unaffected 6.6.160 – ≤ 6.6.*
- unaffected 6.12.114 – ≤ 6.12.*
- unaffected 6.18.57 – ≤ 6.18.*
- unaffected 7.1.4 – ≤ 7.1.*
- unaffected 7.2 – ≤ *
References
References6
- https://git.kernel.org/stable/c/c0fe1118a1471d459f76c3e70ff2abbf784ce6bf (opens in a new tab)
- https://git.kernel.org/stable/c/6825a45f6b8ef76b0ee32649ec3d6e39ca143a18 (opens in a new tab)
- https://git.kernel.org/stable/c/27ead8c5418af6bfab711079fecb9414d78d4cae (opens in a new tab)
- https://git.kernel.org/stable/c/3eaec47518e126e6dcd1a48521d740278073f0ec (opens in a new tab)
- https://git.kernel.org/stable/c/550cfb8a81181331d4d0f76ab75ee58a0bf41e3e (opens in a new tab)
- https://git.kernel.org/stable/c/760ef2c579c2609cf17fb1cd5392f64d42d43d33 (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-48932 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-64388)Record last updated .