Detections
Analytics

Linux Distros Unpatched Vulnerability : CVE-2026-80213

medium Nessus Plugin ID 342194

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.

 - An issue was discovered in the resolv gem before 0.7.2 for Ruby. Resolv::DNS::MessageEncoder wrote a DNS label's length into a single octet without checking its range. A label longer than 255 octets had its length stored modulo 256 but the label data was written unchanged, and thus the bytes on the wire described a different name than the one the application asked to encode. RFC 1035 section 2.3.4 limits a label to 63 octets, and the two high bits of the length octet are reserved for compression pointers.
 put_string packed the length with put_pack(C, d.length) and put_label used it for labels, and thus any value from 0 to 255 could end up as a label length octet, including the reserved 0x40-0xBF range and the 0xC0-0xFF pointer range. Resolv::DNS::Name.create did not check per-label or total name length either, and thus an attacker-controlled hostname reached the encoder unchanged. An application that resolves an attacker-controlled hostname sends a query whose wire bytes name a domain the attacker chose. A hostname suffix that the application validates against an allowlist becomes padding that never appears on the wire, and thus allowlist and egress checks can be bypassed. The recursive resolver caches the response under the attacker's name, and DNS logs record that name rather than the one the application asked for. A label length whose low octet lands in the 0xC0-0xFF range produces a length octet that conforming parsers read as the start of a compression pointer, with the following attacker-controlled byte as the offset.
 (CVE-2026-80213)

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://access.redhat.com/security/cve/cve-2026-80213

Plugin Details

Severity: Medium

ID: 342194

File Name: unpatched_CVE_2026_80213.nasl

Version: 1.1

Type: Local

Agent: unix

Family: Misc.

Published: 9/1/2026

Updated: 9/1/2026

Supported Sensors: Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: Low

Score: 1.2

Percentile: 0.01

CVSS v2

Risk Factor: Medium

Base Score: 5

Temporal Score: 4.3

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

CVSS Score Source: CVE-2026-80213

CVSS v3

Risk Factor: Medium

Base Score: 4

Temporal Score: 3.7

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

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

Vulnerability Information

CPE: cpe:/o:centos:centos:8, cpe:/o:redhat:enterprise_linux:10, cpe:/o:redhat:enterprise_linux:8, cpe:/o:redhat:enterprise_linux:9, p-cpe:/a:centos:centos:ruby-bundled-gems, p-cpe:/a:centos:centos:ruby-default-gems, p-cpe:/a:centos:centos:ruby-devel, p-cpe:/a:centos:centos:ruby-doc, p-cpe:/a:centos:centos:ruby-irb, p-cpe:/a:centos:centos:ruby-libs, p-cpe:/a:centos:centos:ruby4.0-devel, p-cpe:/a:centos:centos:ruby4.0-doc, p-cpe:/a:centos:centos:ruby4.0-rubygem-mysql2, p-cpe:/a:centos:centos:ruby4.0-rubygem-pg, p-cpe:/a:centos:centos:ruby4.0, p-cpe:/a:centos:centos:ruby, p-cpe:/a:centos:centos:rubygem-abrt-doc, p-cpe:/a:centos:centos:rubygem-abrt, p-cpe:/a:centos:centos:rubygem-bigdecimal, p-cpe:/a:centos:centos:rubygem-bson-doc, p-cpe:/a:centos:centos:rubygem-bson, p-cpe:/a:centos:centos:rubygem-bundler-doc, p-cpe:/a:centos:centos:rubygem-bundler, p-cpe:/a:centos:centos:rubygem-did_you_mean, p-cpe:/a:centos:centos:rubygem-io-console, p-cpe:/a:centos:centos:rubygem-irb, p-cpe:/a:centos:centos:rubygem-json, p-cpe:/a:centos:centos:rubygem-minitest, p-cpe:/a:centos:centos:rubygem-mongo-doc, p-cpe:/a:centos:centos:rubygem-mongo, p-cpe:/a:centos:centos:rubygem-mysql2-doc, p-cpe:/a:centos:centos:rubygem-mysql2, p-cpe:/a:centos:centos:rubygem-net-telnet, p-cpe:/a:centos:centos:rubygem-openssl, p-cpe:/a:centos:centos:rubygem-pg-doc, p-cpe:/a:centos:centos:rubygem-pg, p-cpe:/a:centos:centos:rubygem-power_assert, p-cpe:/a:centos:centos:rubygem-psych, p-cpe:/a:centos:centos:rubygem-racc, p-cpe:/a:centos:centos:rubygem-rake, p-cpe:/a:centos:centos:rubygem-rbs, p-cpe:/a:centos:centos:rubygem-rdoc, p-cpe:/a:centos:centos:rubygem-rexml, p-cpe:/a:centos:centos:rubygem-rss, p-cpe:/a:centos:centos:rubygem-test-unit, p-cpe:/a:centos:centos:rubygem-typeprof, p-cpe:/a:centos:centos:rubygem-xmlrpc, p-cpe:/a:centos:centos:rubygems-devel, p-cpe:/a:centos:centos:rubygems, p-cpe:/a:redhat:enterprise_linux:ruby-bundled-gems, p-cpe:/a:redhat:enterprise_linux:ruby-default-gems, p-cpe:/a:redhat:enterprise_linux:ruby-devel, p-cpe:/a:redhat:enterprise_linux:ruby-doc, p-cpe:/a:redhat:enterprise_linux:ruby-irb, p-cpe:/a:redhat:enterprise_linux:ruby-libs, p-cpe:/a:redhat:enterprise_linux:ruby4.0-devel, p-cpe:/a:redhat:enterprise_linux:ruby4.0-doc, p-cpe:/a:redhat:enterprise_linux:ruby4.0-rubygem-mysql2, p-cpe:/a:redhat:enterprise_linux:ruby4.0-rubygem-pg, p-cpe:/a:redhat:enterprise_linux:ruby4.0, p-cpe:/a:redhat:enterprise_linux:ruby, p-cpe:/a:redhat:enterprise_linux:rubygem-abrt-doc, p-cpe:/a:redhat:enterprise_linux:rubygem-abrt, p-cpe:/a:redhat:enterprise_linux:rubygem-bigdecimal, p-cpe:/a:redhat:enterprise_linux:rubygem-bson-doc, p-cpe:/a:redhat:enterprise_linux:rubygem-bson, p-cpe:/a:redhat:enterprise_linux:rubygem-bundler-doc, p-cpe:/a:redhat:enterprise_linux:rubygem-bundler, p-cpe:/a:redhat:enterprise_linux:rubygem-did_you_mean, p-cpe:/a:redhat:enterprise_linux:rubygem-io-console, p-cpe:/a:redhat:enterprise_linux:rubygem-irb, p-cpe:/a:redhat:enterprise_linux:rubygem-json, p-cpe:/a:redhat:enterprise_linux:rubygem-minitest, p-cpe:/a:redhat:enterprise_linux:rubygem-mongo-doc, p-cpe:/a:redhat:enterprise_linux:rubygem-mongo, p-cpe:/a:redhat:enterprise_linux:rubygem-mysql2-doc, p-cpe:/a:redhat:enterprise_linux:rubygem-mysql2, p-cpe:/a:redhat:enterprise_linux:rubygem-net-telnet, p-cpe:/a:redhat:enterprise_linux:rubygem-openssl, p-cpe:/a:redhat:enterprise_linux:rubygem-pg-doc, p-cpe:/a:redhat:enterprise_linux:rubygem-pg, p-cpe:/a:redhat:enterprise_linux:rubygem-power_assert, p-cpe:/a:redhat:enterprise_linux:rubygem-psych, p-cpe:/a:redhat:enterprise_linux:rubygem-racc, p-cpe:/a:redhat:enterprise_linux:rubygem-rake, p-cpe:/a:redhat:enterprise_linux:rubygem-rbs, p-cpe:/a:redhat:enterprise_linux:rubygem-rdoc, p-cpe:/a:redhat:enterprise_linux:rubygem-rexml, p-cpe:/a:redhat:enterprise_linux:rubygem-rss, p-cpe:/a:redhat:enterprise_linux:rubygem-test-unit, p-cpe:/a:redhat:enterprise_linux:rubygem-typeprof, p-cpe:/a:redhat:enterprise_linux:rubygem-xmlrpc, p-cpe:/a:redhat:enterprise_linux:rubygems-devel, p-cpe:/a:redhat:enterprise_linux:rubygems

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: 8/27/2026

Reference Information

CVE: CVE-2026-80213