CVE-2026-109411

HIGH

8.1

CVSS v3

Description

An access control bypass flaw was identified in Samba's vfs_ceph_rgw module in it's openat() function. An authenticated user can bypass access controls to read or overwrite restricted files on shares configured with the experimental vfs_ceph_rgw module. When a client requests an existing file using mismatched character casing, the module fails to perform a case-insensitive lookup correctly, causing the server to treat the operation as creating a new file. As a result, the server skips standard permission checks on the existing file, allowing the attacker to access or overwrite sensitive data owned by other users.

CWE-178

How to fix

Remediation Available

sambaDebian

Fixed in:2:4.25.1+dfsg-1CVE-2026-109411

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredLow

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityNone

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

Exploit Intelligence

0.65%probability of exploitation in 30 days

51stpercentile

Moderate risk: more likely to be exploited than 51% of all known CVEs.

References

Other references5

Related Vulnerabilities

Other CWE-178 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2025-27636	Medium	5.6	97%	-	Fix
CVE-2021-24347	High	8.8	54%	-	Fix
CVE-2020-12812	Critical	9.8	45%	KEV + Ransom	Fix
CVE-2003-0411	High	7.5	25%	-	-
CVE-2026-47323	Critical	9.8	20%	-	Fix
CVE-2018-9845	Critical	9.8	13%	-	Fix

Common questions

How do I fix CVE-2026-109411?

Upgrade samba on debian unstable to 2:4.25.1+dfsg-1 or later.

Is CVE-2026-109411 being actively exploited?

Not that we know of. CVE-2026-109411 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.65% is the estimated probability that it will be exploited in the next 30 days. That is higher than 51% of all scored CVEs.

How severe is CVE-2026-109411?

CVE-2026-109411 has a CVSS v3 base score of 8.1, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

What does CVE-2026-109411 affect?

Published advisories record a fix for samba (Debian). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

Embed a live status badge for CVE-2026-109411

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-10-30.