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CVE-2026-86219 on Cyberus Linux 26.05

Aliases: CVE-2026-86219

Packages: perlPackages.AuthenSASL

Status: Plausible

Advisory Information

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.

Updates

2026-09-09 21:31 CEST

Metadata changes:

  • Status for package perlPackages.AuthenSASL: “Plausible”

2026-09-09 21:31 CEST

Metadata changes:

  • Status for package perlPackages.AuthenSASL: “New”