Linux Distros Unpatched Vulnerability : CVE-2026-58221

high Nessus Plugin ID 330478

Synopsis

The Linux/Unix host has one or more packages installed with a vulnerability that the vendor indicates will not be patched.

Description

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

- Samba AD stores internal database configuration in LDB special records such as @MODULES and @PARTITION.
These records are not directory objects and should never be writable by a normal LDAP client. An authenticated low-privilege domain user can nevertheless modify them through LDAP. The LDAP request is correctly marked as untrusted, but `rootdse_filter_operations()` only rejects anonymous callers. The request then reaches the DSDB ACL module, which intentionally skips ACL processing for special DNs because it assumes only trusted internal callers can reach them. This lets an ordinary user replace the DSDB module chain loaded for new LDAP connections. By omitting only acl and aclread, the attacker gets a fully functional LDAP connection without directory ACL enforcement and can add themselves to protected administrator groups. High-signal indicators: - A recent modification timestamp of the main sam.ldb most likely: /var/lib/samba/private/sam.ldb - LDAP operations targeting DNs beginning with `@`; - `@MODULES/@LIST` differing from `samba_dsdb`; - unexpected `@PARTITION/modules` values on a standard provision; - low-privilege accounts added to `Domain Admins`, `Enterprise Admins`, or `Builtin Administrators`; - Samba logs showing unusual module-load failures or module-stack changes. If exploitation is suspected: 1. Stop Samba before editing internal LDB records offline. 2. Confirm `@MODULES/@LIST` is exactly `samba_dsdb`. 3. Remove unexpected `@PARTITION/modules` values offline if present. 4. Remove unauthorized protected-group memberships. 5. Audit privileged group, ACL, GPO/SYSVOL, service-account, and replication changes made during the compromise window. 6. Rotate credentials according to the site's AD recovery plan, including KRBTGT where appropriate. (CVE-2026-58221)

Note that Nessus relies on the presence of the package as reported by the vendor.

Solution

There is no known solution at this time.

Plugin Details

Severity: High

ID: 330478

File Name: unpatched_CVE_2026_58221.nasl

Version: 1.1

Type: Local

Agent: unix

Family: Misc.

Published: 7/29/2026

Updated: 7/29/2026

Supported Sensors: Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.9

Percentile: 58.15

CVSS v2

Risk Factor: Medium

Base Score: 6.5

Temporal Score: 5.5

Vector: CVSS2#AV:N/AC:L/Au:S/C:P/I:P/A:P

CVSS Score Source: CVE-2026-58221

CVSS v3

Risk Factor: High

Base Score: 8.8

Temporal Score: 8.1

Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:U/RL:U/RC:C

Vulnerability Information

CPE: cpe:/o:canonical:ubuntu_linux:14.04:-:lts, cpe:/o:canonical:ubuntu_linux:16.04:-:lts, cpe:/o:canonical:ubuntu_linux:18.04:-:lts, cpe:/o:canonical:ubuntu_linux:20.04:-:lts, cpe:/o:debian:debian_linux:11.0, cpe:/o:debian:debian_linux:12.0, cpe:/o:debian:debian_linux:14.0, p-cpe:/a:canonical:ubuntu_linux:samba, p-cpe:/a:debian:debian_linux:samba

Required KB Items: Host/cpu, Host/local_checks_enabled, global_settings/vendor_unpatched, Host/OS/identifier

Exploit Ease: No known exploits are available

Vulnerability Publication Date: 7/28/2026

Reference Information

CVE: CVE-2026-58221

Detections

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