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Linux Distros Unpatched Vulnerability : CVE-2026-123603

medium Nessus Plugin ID 377638

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.

 - hickory-proto and hickory-resolver 0.26.0 before 0.26.2, hickory-server 0.25.0-alpha.1 before 0.26.2, and hickory-recursor 0.25.0-alpha.3 through 0.26.0-alpha.1 fail to canonicalize IPv4-mapped IPv6 addresses when checking deny_answers, deny_server, or AccessControlSet rules. Attackers can use IPv4-mapped addresses to evade answer filtering, trigger queries to denied nameservers, or reach hickory-server library deployments on dual-stack IPv6 sockets from denied clients. (CVE-2026-123603)

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-2026-123603

Plugin Details

Severity: Medium

ID: 377638

File Name: unpatched_CVE_2026_123603.nasl

Version: 1.1

Type: Local

Agent: unix

Family: Misc.

Published: 11/9/2026

Updated: 11/9/2026

Supported Sensors: Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: Low

Score: 2.1

Percentile: 8.42

CVSS v3

Risk Factor: Medium

Base Score: 6.5

Temporal Score: 6

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

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

CVSS Score Source: CVE-2026-123603

CVSS v4

Risk Factor: Medium

Base Score: 6.9

Threat Score: 2.7

Threat Vector: CVSS:4.0/E:U

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

CVSS Score Source: CVE-2026-123603

Vulnerability Information

CPE: cpe:/o:debian:debian_linux:13.0, cpe:/o:debian:debian_linux:14.0, p-cpe:/a:debian:debian_linux:rust-hickory-proto, p-cpe:/a:debian:debian_linux:rust-hickory-recursor, p-cpe:/a:debian:debian_linux:rust-hickory-resolver, p-cpe:/a:debian:debian_linux:rust-hickory-server

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: 11/8/2026

Reference Information

CVE: CVE-2026-123603