# CVE-2026-86219

> As of 2026-09-06, CVE-2026-86219 is a vulnerability, EPSS 0.2% (12.1th percentile). No Threadlinqs-tracked threat campaign has been attributed to CVE-2026-86219 as of 2026-09-06; the identifier is re-checked against the Threadlinqs threat corpus on every daily ingest.

**Last updated:** 2026-09-06

## 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](https://intel.threadlinqs.com/cwe/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 2026-09-07. This product uses the NVD API but is not endorsed or certified by the NVD.

**Vendor advisory and patch**

- [github.com — patch](https://github.com/perl-authen-sasl/perl-authen-sasl/commit/94337367030612842924f697cead29964a96448d.patch)
- [metacpan.org — release notes](https://metacpan.org/release/EHUELS/Authen-SASL-2.2100/changes)

**Other references**

- [metacpan.org](https://metacpan.org/release/EHUELS/Authen-SASL-2.2000/source/lib/Authen/SASL/Perl/DIGEST_MD5.pm#L203-222)
- [metacpan.org (DIGEST MD5)](https://metacpan.org/release/EHUELS/Authen-SASL-2.2000/source/lib/Authen/SASL/Perl/DIGEST_MD5.pm#L410-414)
- [datatracker.ietf.org](https://datatracker.ietf.org/doc/html/rfc2831#section-2.1.2)
- [cve.org — related](https://www.cve.org/CVERecord?id=CVE-2025-40918)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-86219
Full detection coverage and IOCs for threats exploiting CVE-2026-86219 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp