VulnerabilityPublished 24 Sep 2026Updated 30 Oct 2026

CVE-2026-93786: Linux kernel · ksmbd: preserve VFS inherited POSIX ACL mask

Affects Linux kernelSource CVE Database V5

Not known to be exploited · CVSS 8.1 High · fixed in e148e567a9252643baa125cb65d7ae9c2c6cf68a : patch Linux kernel soon.

Data as of 30 Oct 2026, 13:04 UTC

CVSS 3.1 base score

8.1High

How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none

CVSS scores by source
CNA (Linux)	CVSS 3.1	8.1

Patch: Available – fixed in e148e567a9252643baa125cb65d7ae9c2c6cf68a, 0093909becbda22b62b39b654dbc607faed59cd0, 8493da704275ca5ab67fb88c0ae7b71576e91951 +2

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: Low
User Interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: High
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 24 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ f44158485826c076335d6860d35872271a83791d, < e148e567a9252643baa125cb65d7ae9c2c6cf68a	Fixed in e148e567a9252643baa125cb65d7ae9c2c6cf68a
LinuxLinux	Affected ≥ f44158485826c076335d6860d35872271a83791d, < 0093909becbda22b62b39b654dbc607faed59cd0	Fixed in 0093909becbda22b62b39b654dbc607faed59cd0
LinuxLinux	Affected ≥ f44158485826c076335d6860d35872271a83791d, < 8493da704275ca5ab67fb88c0ae7b71576e91951	Fixed in 8493da704275ca5ab67fb88c0ae7b71576e91951
LinuxLinux	Affected ≥ f44158485826c076335d6860d35872271a83791d, < 591acf171644de590cda245fd8595b473a1beb70	Fixed in 591acf171644de590cda245fd8595b473a1beb70
LinuxLinux	Affected ≥ f44158485826c076335d6860d35872271a83791d, < 4a19bb1c45667f5a5f6eff9cf6648e0f692d046f	Fixed in 4a19bb1c45667f5a5f6eff9cf6648e0f692d046f
LinuxLinux	Affected =5.15	Fixed in–

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AI-suggested

A fix is available and has been applied in the Linux kernel versions identified by the fixed commit hashes. Users should update to a Linux kernel version that includes these fixes to remediate the vulnerability. Since this is not a cloud service, manual patching is required.

Description

CVE-2026-93786 addresses a vulnerability in the Linux kernel's ksmbd component related to POSIX ACL mask handling. The issue involved improper mutation of the parent's ACL or overwriting of the child's VFS-computed access and default ACLs, which could widen effective permissions during SMB object creation. The fix preserves restrictive ACL_MASK entries to prevent unauthorized permission escalation.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 30 Oct 2026, 12:50 UTC

Technical details

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