CVE-2026-86219 Affecting libauthen-sasl-perl package, versions <2.2000-1ubuntu0.1


Severity

Recommended
medium

Based on Ubuntu security rating.

Threat Intelligence

EPSS
0.47% (38th percentile)

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  • Snyk IDSNYK-UBUNTU2604-LIBAUTHENSASLPERL-19638475
  • published1 Oct 2026
  • disclosed6 Sept 2026

Introduced: 6 Sep 2026

CVE-2026-86219  (opens in a new tab)

How to fix?

Upgrade Ubuntu:26.04 libauthen-sasl-perl to version 2.2000-1ubuntu0.1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream libauthen-sasl-perl package and not the libauthen-sasl-perl package as distributed by Ubuntu. See How to fix? for Ubuntu:26.04 relevant fixed versions and status.

Authen::SASL::Perl::DIGEST_MD5 versions before 2.2100 for Perl accept replayed authentication responses via unverified nonce in server_step.

server_start generates a fresh nonce and sends it in the challenge, and nothing later compares that value against the nonce the client returns. server_step derives the expected digest from the client's own parameters, so a response verifies whenever its digest matches the nonce it carries. The count table it also checks is keyed on the client-supplied nonce and starts empty in each new server object, so a captured first response, carrying nc=00000001, passes that too. RFC 2831 defines the nonce in the response as the value the server sent in the preceding challenge.

An attacker who observes one successful qop=auth exchange can replay the captured response against a later session for the same service, host, realm and user, and authenticate as that user without knowing the password.

CVSS Base Scores

version 3.1