Detections
Analytics
Linux Distros Unpatched Vulnerability : CVE-2026-58222
high Nessus Plugin ID 330477
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's LDAP CompareRequest path contains two independent security flaws that can be combined by an authenticated attacker to construct a reliable oracle for protected (confidential) Active Directory attributes. 1. Filter Injection Flaw When processing an LDAP Compare request, Samba constructs a textual LDB filter by directly formatting the user-provided attribute name and assertion value into a search filter string using talloc_asprintf(): filter = talloc_asprintf(local_ctx, (%s=%*s), req->attribute, (int)req->value.length, req->value.data); This formulation is unsafe because: - The attribute name is not validated as a valid LDAP AttributeDescription. - The assertion value is not escaped. - The field format (%*s) does not properly handle binary or BER-encoded bytes. By providing an attribute name containing filter operators (for example, appending >= to the attribute name), an attacker can coerce Samba into evaluating a comparison operator other than equality. 2. Trusted Search Context Flaw Samba evaluates the generated filter using an internal local LDB search request without marking it as untrusted. Normal LDAP search requests enforce access controls by marking requests from unprivileged connections as untrusted.
The ACL read module uses this marker to determine whether it must enforce visibility checks. Because Compare requests do not mark the database search as untrusted, they are evaluated with trusted system- level visibility, bypassing standard ACL checks for confidential attributes. Combining these two flaws, an ordinary authenticated domain user can issue ordered true/false Compare queries (e.g. using inequality operators like >=) to binary-search and reconstruct binary values of confidential attributes that are normally redacted from LDAP Search results. A key target for this attack is the msKds-RootKeyData attribute, which contains the root secret for the Group Key Distribution Service (GKDI). On Samba AD DC installations supporting Group Managed Service Accounts (gMSAs) (Samba 4.21.0 and later), an attacker can extract this key and derive the passwords of gMSAs offline. If a privileged gMSA exists, this allows full domain compromise. (CVE-2026-58222)
Note that Nessus relies on the presence of the package as reported by the vendor.
Solution
There is no known solution at this time.See Also
Plugin Details
Severity: High
ID: 330477
File Name: unpatched_CVE_2026_58222.nasl
Version: 1.1
Type: Local
Agent: unix
Family: Misc.
Published: 7/29/2026
Updated: 7/29/2026
Supported Sensors: Agentless Assessment, Frictionless Assessment Agent, Frictionless Assessment AWS, Frictionless Assessment Azure, Nessus Agent, Tenable Cloud Security, Tenable Self-Hosted Container Security, Nessus
Risk Information
VPR
Risk Factor: Low
Score: 3
Percentile: 23.73
CVSS v2
Risk Factor: Medium
Base Score: 5.5
Temporal Score: 4.7
Vector: CVSS2#AV:N/AC:L/Au:S/C:P/I:P/A:N
CVSS Score Source: CVE-2026-58222
CVSS v3
Risk Factor: High
Base Score: 8.1
Temporal Score: 7.4
Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
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-2026-58222