ksmbd: reject undersized DACLs before parsing ACEs
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Partial Red Hat: 1 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.
Summary
In the Linux kernel, the following vulnerability has been resolved: ksmbd: reject undersized DACLs before parsing ACEs parse_dacl() limits the attacker-controlled ACE count by comparing it with the number of minimal ACEs that fit in the DACL size. The DACL size field is 16 bits, but the expression subtracts sizeof(struct smb_acl). Because sizeof() is unsigned, a DACL size smaller than the ACL header underflows to a large size_t. A malicious client can reach this with: SMB2_SET_INFO (InfoType=SMB2_O_INFO_SECURITY) -> smb2_set_info_sec() -> set_info_sec() -> parse_sec_desc() -> parse_dacl() -> init_acl_state(..., 0xffff) -> init_acl_state(..., 0xffff) -> kmalloc_objs(..., 0xffff) Thus a malformed security descriptor can make num_aces pass the guard and drive large temporary ACL state and pointer-array allocations. Reject DACLs smaller than struct smb_acl before doing the subtraction, so the ACE count check cannot be bypassed by the underflow.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
Remediation
- Fix · CNA Linux (Linux) Fixed in 6.1.191, 6.6.145, 6.12.97, 6.18.40, 7.1.5, 7.2
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
Not affected: 4 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
Timeline
- 2026-10-02 Threatist record created from CVE-2026-72382
- 2026-10-03 Alias added: GHSA-xrhm-hwvc-w6q3
- 2026-10-26 Affected versions changed · Red Hat
- 2026-10-26 CVSS score changed · Red Hat
- 2026-10-27 EPSS moved to the 50th–90th percentile
- 2026-10-30 Fix available: Linux/[email protected], Linux/Linux@8dc949061e35427433feac3ebe5ec089f2aa857e · CNA
- 2026-10-30 1 new reference · CNA
References
Other 6
- https://git.kernel.org/stable/c/8dc949061e35427433feac3ebe5ec089f2aa857e
- https://git.kernel.org/stable/c/16fb65ec15fe7c90f50a2115854bfd9a032d4023
- https://git.kernel.org/stable/c/282847c0cf22f2e961155ac8e42f6eeab7e16049
- https://git.kernel.org/stable/c/d020e7f27bf65eecd3805404702f716b2b6d9e73
- https://git.kernel.org/stable/c/15a9e9b8f7f5d7f380ae54c6f5bcbc0bdcb0f3cd
- https://git.kernel.org/stable/c/60908f7ebcd9b6cde74ad5711fab0f49c7970949
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Sources
- CVE-2026-72382 · CVE Program
- CVE-2026-72382 · NVD
- FIRST EPSS
- GHSA-xrhm-hwvc-w6q3 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-72382 · Red Hat security data · CC BY 4.0
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