CVE-2026-99110smb: client: fix heap overflow in cifs_do_set_acl()
- 7.0HighCVSS 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 heap overflow in cifs_do_set_acl() cifs_set_acl() validates ACL size using posix_acl_xattr_size(): 4 + (count * 8) // 4-byte header + 8 bytes per ACE cifs_do_set_acl() then calls posix_acl_to_cifs() to write the CIFS wire format into the same buffer: 6 + (count * 10) // 6-byte header + 10 bytes per ACE An ACL that passes the xattr-based check in cifs_set_acl() can overflow the heap when posix_acl_to_cifs() writes the larger CIFS format. Validate the CIFS format size against the remaining buffer space and USHRT_MAX before converting--data_count is __u16, so sizes above USHRT_MAX truncate the on-wire packet length, causing the server to apply a partial ACL. Replace MaxDataCount = 1000 with min(CIFSMaxBufSize, USHRT_MAX).
Timeline
ID reserved
By Linux
- 33 days later
· 33 days later
Published
- 3 days later
· 3 days 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 | High7.0 | CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H |
| NVDNVD · Received | 3.1 | High7.0 | CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 0.13% · top 97% of all CVEs (13 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.0.
Affected products
- affected dc1af4c4b4721abfa07b351063825acc7e69cc66 – < 68652afb9b9adf70125971abee9b95341e042249
- affected dc1af4c4b4721abfa07b351063825acc7e69cc66 – < 9312a00215602ba028495ef3fa00fb84af0478e0
- affected dc1af4c4b4721abfa07b351063825acc7e69cc66 – < d96f3365ce61c5f39602955af43c8174548dee98
- affected dc1af4c4b4721abfa07b351063825acc7e69cc66 – < 596b4062e6c75bdd85a7f2b7f2087a872dc420ac
- affected dc1af4c4b4721abfa07b351063825acc7e69cc66 – < 1dac61e2c29d1a71784604b48cf3b1234a65ec29
- affected 6.2
- unaffected < 6.2
- unaffected 6.6.161 – ≤ 6.6.*
- unaffected 6.12.115 – ≤ 6.12.*
- unaffected 6.18.59 – ≤ 6.18.*
- unaffected 7.2.13 – ≤ 7.2.*
- unaffected 7.3 – ≤ *
References
References5
- https://git.kernel.org/stable/c/68652afb9b9adf70125971abee9b95341e042249 (opens in a new tab)
- https://git.kernel.org/stable/c/9312a00215602ba028495ef3fa00fb84af0478e0 (opens in a new tab)
- https://git.kernel.org/stable/c/d96f3365ce61c5f39602955af43c8174548dee98 (opens in a new tab)
- https://git.kernel.org/stable/c/596b4062e6c75bdd85a7f2b7f2087a872dc420ac (opens in a new tab)
- https://git.kernel.org/stable/c/1dac61e2c29d1a71784604b48cf3b1234a65ec29 (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-2026-112010 (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-2026-99110)Record last updated .