CVE•Published 2026-03-27•Modified 2026-04-29•0 articles on news•5 live references•NVD data

CVE-2026-27855Dovecot · Dovecot

Vulnerability data via NVD (ingested)

CVSS v3.1

6.8

MEDIUM

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N

EPSS percentile

Exploit Prediction Scoring System · top 86% of all CVEs

Weaknesses (CWE)

CWE-294Authentication Bypass by Capture-replay

Description

Dovecot OTP authentication is vulnerable to replay attack under specific conditions. If auth cache is enabled, and username is altered in passdb, then OTP credentials can be cached so that same OTP reply is valid. An attacker able to observe an OTP exchange is able to log in as the user. If authentication happens over unsecure connection, switch to SCRAM protocol. Alternatively ensure the communcations are secured, and if possible switch to OAUTH2 or SCRAM. No publicly available exploits are known.

Timeline

Published 2026-03-27

Modified 2026-04-29

External references

NVD MITRE Exploit-DB Sploitus VulnCheck

Search for exposed instances

Shodan + Censys queries derived from NVD's CPE data. The vuln tag catches assets Shodan has explicitly linked to this CVE; the product / banner fingerprints find exposed instances even when the vuln tag was never applied (which is common).

Shodan · vuln tag204 hosts

vuln:CVE-2026-27855

Hosts Shodan has explicitly fingerprinted as vulnerable.

Shodan · product

product:"Dovecot Dovecot"

All exposed Dovecot Dovecot instances — cross-reference with the CVE's affected-version range.

Shodan · banner/body mention

http.html:"Dovecot"

HTTP body or banner mentions "Dovecot" — catches deploys Shodan didn't identify as a product.

More intel sources (5)

Shodan report

vuln:CVE-2026-27855