PT-2026-2106 · Mailpit · Mailpit

Omarkurt · Published 2026-01-06 · Updated 2026-03-27 · CVE-2026-21859

Positive Technologies (AI Summary)

CVSS v3.1

5.8

Medium

Base vector

AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N

Name of the Vulnerable Software and Affected Versions Mailpit versions 1.28.0 and below

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

Recommendations Update Mailpit to version 1.28.1 or later.

Exploit

Fix

SSRF

Weakness Enumeration

CWE-918

Related Identifiers

CVE-2026-21859

GHSA-8V65-47JX-7MFR

GO-2026-4284

SUSE-SU-2026:0142-1

Affected Products

Mailpit

References · 50

• 🔥 https://github.com/axllent/mailpit/security/advisories/GHSA-8v65-47jx-7mfr · Exploit
• 🔥 https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/21xxx/CVE-2026-21859.json · Exploit
• https://github.com/axllent/mailpit/commit/3b9b470c093b3d20b7d751722c1c24f3eed2e19d · Patch
• https://osv.dev/vulnerability/CVE-2026-21859 · Vendor Advisory
• https://osv.dev/vulnerability/SUSE-SU-2026:0142-1 · Vendor Advisory
• https://osv.dev/vulnerability/GHSA-8v65-47jx-7mfr · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-21859 · Security Note
• https://osv.dev/vulnerability/GO-2026-4284 · Vendor Advisory
• https://github.com/axllent/mailpit · Note
• https://suse.com/security/cve/CVE-2025-63389 · Note
• https://twitter.com/Crowd_Security/status/2028449282458570894 · Twitter Post
• https://t.me/cveNotify/150624 · Telegram Post
• https://suse.com/security/cve/CVE-2026-21885 · Note
• https://suse.com/security/cve/CVE-2026-21859 · Note
• https://suse.com/security/cve/CVE-2025-68151 · Note