CVE•Published 2026-01-08•1 article on news•5 live references•NVD data

CVE-2026-21859

Vulnerability data via CVEDB (Shodan)

CVSS v3.1

5.8

MEDIUM

EPSS percentile

Exploit Prediction Scoring System · top 44% of all CVEs

Description

Mailpit is an email testing tool and API for developers. Versions 1.28.0 and below have a Server-Side Request Forgery (SSRF) vulnerability in the /proxy endpoint, allowing attackers to make requests to internal network resources. The /proxy endpoint validates http:// and https:// schemes, but it does not block internal IP addresses, enabling attackers to access internal services and APIs. This vulnerability is limited to HTTP GET requests with minimal headers. The issue is fixed in version 1.28.1.

Timeline

Published 2026-01-08

External references

NVD MITRE Exploit-DB trickest/cve 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 tag0 hosts

vuln:CVE-2026-21859

Hosts Shodan has explicitly fingerprinted as vulnerable.

Shodan · product + version

product:"Axllent Mailpit" version:"0.0.1"

Version-pinned fingerprint from NVD's first vulnerable CPE.

Shodan · banner/body mention

http.html:"Mailpit"

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

More intel sources (5)

Shodan report

vuln:CVE-2026-21859