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Linux Distros Unpatched Vulnerability : CVE-2026-35563

high Nessus Plugin ID 318281

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.

 - It was identified that the LDAP client implementation in version 2.1.7 does not verify if the server certificate matches the intended LDAP hostname. While the underlying code validates the certificate chain against a trusted authority, the absence of endpoint identification allows a valid certificate issued for an entirely unrelated host to be improperly accepted. This oversight leaves the connection highly vulnerable to server impersonation and complete connection compromise. The root cause of this vulnerability lies in the incomplete TLS server identity verification within the LDAP client implementation. The attacker requires MITM capability on the network to exploit this vulnerability. This attacker must be able to present a certificate trusted by the client's configured trust store. The hostname verification has been enforced in the new version of the LDAP API (CVE-2026-35563)

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

https://security-tracker.debian.org/tracker/CVE-2026-35563

https://ubuntu.com/security/CVE-2026-35563

Plugin Details

Severity: High

ID: 318281

File Name: unpatched_CVE_2026_35563.nasl

Version: 1.1

Type: Local

Agent: unix

Family: Misc.

Published: 6/3/2026

Updated: 6/3/2026

Supported Sensors: Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: High

Score: 7.3

CVSS v2

Risk Factor: High

Base Score: 8.5

Temporal Score: 7.2

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

CVSS Score Source: CVE-2026-35563

CVSS v3

Risk Factor: High

Base Score: 7.4

Temporal Score: 6.8

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

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

CVSS v4

Risk Factor: High

Base Score: 8.8

Threat Score: 5.9

Threat Vector: CVSS:4.0/E:U

Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:H/SI:L/SA:L

Vulnerability Information

CPE: cpe:/o:debian:debian_linux:11.0, cpe:/o:canonical:ubuntu_linux:20.04:-:lts, cpe:/o:canonical:ubuntu_linux:25.10, cpe:/o:canonical:ubuntu_linux:24.04:-:lts, cpe:/o:canonical:ubuntu_linux:16.04:-:lts, cpe:/o:canonical:ubuntu_linux:18.04:-:lts, p-cpe:/a:debian:debian_linux:apache-directory-api, cpe:/o:debian:debian_linux:13.0, cpe:/o:canonical:ubuntu_linux:22.04:-:lts, cpe:/o:debian:debian_linux:14.0, cpe:/o:debian:debian_linux:12.0, p-cpe:/a:canonical:ubuntu_linux:apache-directory-api, cpe:/o:canonical:ubuntu_linux:26.04:-:lts

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

Exploit Ease: No known exploits are available

Vulnerability Publication Date: 6/1/2026

Reference Information

CVE: CVE-2026-35563