CVE-2026-68099ksmbd: restore DACL size on check_add_overflow() to avoid malformed ACL
- —Not scoredno CVSS score yet
- 0.17%Exploitation in 30 daysEPSS · top 93% 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: ksmbd: restore DACL size on check_add_overflow() to avoid malformed ACL check_add_overflow() unconditionally writes the truncated sum into *d even on overflow, per its contract in include/linux/overflow.h. The four check_add_overflow() guards in set_posix_acl_entries_dacl() and set_ntacl_dacl() break out of the ACE-building loops on overflow, but the truncated *size is then consumed downstream at the end of set_ntacl_dacl(): pndacl->size = cpu_to_le16(le16_to_cpu(pndacl->size) + size); This produces an on-wire NT ACL whose pndacl->size under-reports the bytes actually written by the preceding fill_ace_for_sid()/memcpy() calls, yielding a malformed ACL that can trigger out-of-bounds reads when re-parsed by clients or ksmbd itself. Restore *size to its pre-addition value on each overflow branch (via `*size -= ace_sz` / `size -= nt_ace_size`) so that after the break, *size once again holds the cumulative size of the successfully-written ACEs. The committed ACL is then truncated-but-self-consistent rather than malformed. The ksmbd DACL builders are the only check_add_overflow() sites found where an overflow path breaks out of a loop and the destination value is consumed afterward. The other nearby break-style cases either return -EINVAL on overflow (transport_ipc.c) or break without consuming the overflowed destination value afterward (buildid.c).
Timeline
ID reserved
By Linux
- 11 days later
· 11 days later
Published
- 13 days later
· 13 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
No CVSS score yet: neither the CNA, CISA nor NVD has scored this CVE. NVD status: Received.
- EPSS (exploitation in 30 days)
- 0.17% · top 93% of all CVEs (13 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Not scored.
Affected products
- affected 41e53a773db6342ac9a689ee5ba635c31744c9f0 – < 8f3a7a499a7d9bb1c0f33fe78c4a4594d7e307f4
- affected 8d5729350b236896f51379588d9a690b7fafb8db – < f4fcd0c1a243d449307b887fafee23921e9db5ab
- affected e1955a94b6f17f4b058afa955a6f187eb3ed7615 – < 0bf38372821b1526f31538a7d9811844c55c7f38
- affected 5e7b8f3c539d69b2ed5f2408e2f75e68ce7eef43 – < 847ecd4eb3c117c3d2f13f1e7ab506543aad8183
- affected 299f962c0b02d048fb45d248b4da493d03f3175d – < bc90144ce8bb7fcf05ad9417c7adb4e9509d9e13
- affected 299f962c0b02d048fb45d248b4da493d03f3175d – < bbf0a8e931204ecdab494a88d43b0a24a04285c5
- affected ef7902be3f215b6bf7babe4dc9dd9a7d57dad7a7
- affected 6.1.175 – < 6.1.184
- affected 6.6.136 – < 6.6.148
- affected 6.12.84 – < 6.12.101
- affected 6.18.25 – < 6.18.42
- affected 7.0.2 – < 7.1
- affected 7.1
- unaffected < 7.1
- unaffected 6.1.184 – ≤ 6.1.*
- unaffected 6.6.148 – ≤ 6.6.*
- unaffected 6.12.101 – ≤ 6.12.*
- unaffected 6.18.42 – ≤ 6.18.*
- unaffected 7.1.6 – ≤ 7.1.*
- unaffected 7.2 – ≤ *
References
References6
- https://git.kernel.org/stable/c/8f3a7a499a7d9bb1c0f33fe78c4a4594d7e307f4 (opens in a new tab)
- https://git.kernel.org/stable/c/f4fcd0c1a243d449307b887fafee23921e9db5ab (opens in a new tab)
- https://git.kernel.org/stable/c/0bf38372821b1526f31538a7d9811844c55c7f38 (opens in a new tab)
- https://git.kernel.org/stable/c/847ecd4eb3c117c3d2f13f1e7ab506543aad8183 (opens in a new tab)
- https://git.kernel.org/stable/c/bc90144ce8bb7fcf05ad9417c7adb4e9509d9e13 (opens in a new tab)
- https://git.kernel.org/stable/c/bbf0a8e931204ecdab494a88d43b0a24a04285c5 (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-2026-55480 (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)
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[](https://cveledger.app/cve/CVE-2026-68099)Record last updated .