Linux Distros Unpatched Vulnerability : CVE-2026-27624

critical Nessus Plugin ID 299987

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.

- Coturn is a free open source implementation of TURN and STUN Server. Coturn is commonly configured to block loopback and internal ranges using denied-peer-ip and/or default loopback restrictions.
CVE-2020-26262 addressed bypasses involving 0.0.0.0, [::1] and [::], but IPv4-mapped IPv6 is not covered. When sending a CreatePermission or ChannelBind request with the XOR-PEER-ADDRESS value of ::ffff:127.0.0.1, a successful response is received, even though 127.0.0.0/8 is blocked via denied- peer-ip. The root cause is that, prior to the updated fix implemented in version 4.9.0, three functions in src/client/ns_turn_ioaddr.c do not check IN6_IS_ADDR_V4MAPPED. ioa_addr_is_loopback() checks 127.x.x.x (AF_INET) and ::1 (AF_INET6), but not ::ffff:127.0.0.1. ioa_addr_is_zero() checks 0.0.0.0 and ::, but not ::ffff:0.0.0.0. addr_less_eq() used by ioa_addr_in_range() for denied- peer-ip matching: when the range is AF_INET and the peer is AF_INET6, the comparison returns 0 without extracting the embedded IPv4. Version 4.9.0 contains an updated fix to address the bypass of the fix for CVE-2020-26262. (CVE-2026-27624)

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-2026-27624

Plugin Details

Severity: Critical

ID: 299987

File Name: unpatched_CVE_2026_27624.nasl

Version: 1.1

Type: local

Agent: unix

Family: Misc.

Published: 2/26/2026

Updated: 2/26/2026

Supported Sensors: Nessus Agent, Nessus

Risk Information

CVSS v2

Risk Factor: High

Base Score: 7.5

Temporal Score: 6.4

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

CVSS Score Source: CVE-2026-27624

CVSS v3

Risk Factor: Critical

Base Score: 9.8

Temporal Score: 9

Vector: CVSS:3.0/AV:N/AC:L/PR:N/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:debian:debian_linux:11.0, cpe:/o:debian:debian_linux:14.0, p-cpe:/a:debian:debian_linux:coturn, cpe:/o:debian:debian_linux:12.0, cpe:/o:debian:debian_linux:13.0

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: 2/25/2026

Reference Information

CVE: CVE-2026-27624