CVE Catalog

CVE-2026-86219

CriticalCVSS 9.8
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.22%

12th percentile - higher than 12% of all known CVEs

Summary

A vulnerability in Authen::SASL::Perl::DIGEST_MD5 for Perl before version 2.2100 allows acceptance of replayed authentication responses due to an unverified nonce in server_step. An attacker who observes a successful qop=auth exchange can replay the captured response in a later session and authenticate as that user without knowing the password.

Risk Assessment

The vulnerability could allow an attacker to hijack user sessions in services using DIGEST-MD5, potentially leading to unauthorized access to accounts and data.

Recommendation

It is recommended to upgrade Authen::SASL to version 2.2100 or later and consider using more secure authentication mechanisms if possible.

Related vulnerabilities

Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS