What is CVE-2026-86219?
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.
The record classifies CVE-2026-86219 under weakness class CWE-294. The identifier was first published 29 days ago.
Severity and exploitation probability
- EPSS (FIRST)
- 0.2% probability of exploitation in the next 30 days, higher than 12.1% of all scored CVEs
- CISA KEV
- Not listed in the CISA Known Exploited Vulnerabilities catalog
- Threadlinqs priority
- 0.5/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- Published
- 2026-09-06
Is CVE-2026-86219 being exploited?
It currently carries a trending score of 33 in the Threadlinqs vulnerability feed.
Affected products and versions
No affected-product or package list has been recorded for CVE-2026-86219 in the tracked sources. The vendor advisory and the references below are the authoritative statement of what is affected.
How to fix CVE-2026-86219
No vendor patch reference has been recorded for CVE-2026-86219 in the tracked sources. Follow the references below for a fix, and treat any affected deployment as exposed until the vendor states otherwise.
Threat activity tracking CVE-2026-86219
No threat campaign in the Threadlinqs corpus currently references CVE-2026-86219, in its CVE list or as an indicator. The linkage is recomputed from the live corpus on every daily ingest, so this section fills in as soon as a tracked campaign cites the identifier.
Sources
Enriched from CVE.org, NVD, GitHub Security Advisories, FIRST EPSS. Last verified by Threadlinqs on . This product uses the NVD API but is not endorsed or certified by the NVD.