CVE-2026-27808 Mailpit is Vulnerable to Server-Side Request Forgery (SSRF) via Link Check API
Attackers can exploit the Link Check API to perform Server-Side Request Forgery, accessing internal resources and bypassing network restrictions.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-27808?
CVE-2026-27808 is a medium-severity server-side request forgery vulnerability in axllent mailpit, published on 25 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Mailpit is an email testing tool and API for developers. Prior to version 1.29.2, the Link Check API (/api/v1/message/{ID}/link-check) is vulnerable to Server-Side Request Forgery (SSRF). The server performs HTTP HEAD requests to every URL found in an email without validating target hosts or filtering private/internal IP addresses. The response returns status codes and status text per link, making this a non-blind SSRF. In the default configuration (no authentication on SMTP or API), this is fully exploitable remotely with zero user interaction. This is the same class of vulnerability that was fixed in the HTML Check API (CVE-2026-23845 / GHSA-6jxm-fv7w-rw5j) and the screenshot proxy (CVE-2026-21859 / GHSA-8v65-47jx-7mfr), but the Link Check code path was not included in either fix. Version 1.29.2 fixes this vulnerability.
Weakness: CWE-918
Which versions are affected by CVE-2026-27808?
3 open source packages ship an affected version, including github.com/axllent/mailpit. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
github.com/axllent/mailpit Go | All versions | 1.29.2 |
github.com/axllent/mailpit Go | All versions | 1.29.2 |
github.com/axllent/mailpit Go | All versions | 1.29.2 |
Products include Axllent Mailpit.
How do I fix CVE-2026-27808?
Upgrade github.com/axllent/mailpit to 1.29.2 or later.
Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.
Is CVE-2026-27808 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-27808 exists.
Other vulnerabilities in axllent mailpit
- CVE-2026-45713 Mailpit: Unauthenticated remote memory-exhaustion DoS via unlimited SMTP DATA and /api/v1/send body sizes
- CVE-2026-22689 Mailpit is vulnerable to Cross-Site WebSocket Hijacking (CSWSH) allowing unauthenticated access to emails
- CVE-2026-45711 Mailpit: Path traversal & arbitrary file write in mailpit dump --http via attacker-controlled message IDs
- CVE-2026-45712 Mailpit: Concurrent map read & write in proxy CSS rewriter - remote unauth crash (fatal error: concurrent map read and map write)
- CVE-2026-45709 Mailpit has an incomplete fix for GHSA-6jxm: HTML check still permits SSRF to private/loopback/IMDS via missing IP-filter dialer
Sources
Also known as GHSA-mpf7-p9x7-96r3, GO-2026-4558.