CVE-2026-109411

HIGH
MEDIUM Priority: 0.05 BB Relevance: 66/100
Published: 2026-10-28 Modified: 2026-10-29 First seen: 2026-10-29 Status: active

Attack Surface

Network Low Complexity No Interaction Conf. Impact Integ. Impact

CVSS Vector Breakdown

AV: Network
AC: Low
PR: Low
UI: None
S: Unchanged
C: High
I: High
A: None

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.

Weakness Classification (1)

Affected Software (2)

VendorProductVersion
Samba Samba 4.25.0 < 4.25.1
Samba Samba 4.25.0 < 4.25.1

Bug Bounty Relevance

66 / 100
✓ Network accessible
✓ Low complexity
✓ No user interaction

CVSS Score

8.1 / 10.0 v3.1
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

EPSS — Exploitation Probability

0.65%
Raw Score 0.006490
Percentile 51.0%
Date 2026-10-29

Intelligence Sources

mitre ref →
nvd ref →