CVE-2026-45711 Mailpit: Path traversal & arbitrary file write in mailpit dump --http via attacker-controlled message IDs
A malicious server can exploit path traversal in Mailpit's dump command to write arbitrary files outside the intended directory, potentially leading to code execution.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-45711?
CVE-2026-45711 is a medium-severity path traversal vulnerability in axllent mailpit, published on 20 Jul 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
Mailpit is an email testing tool and API for developers. Prior to version 1.30.0, the mailpit dump --http <base-url> <out-dir> sub-command downloads every message from a remote Mailpit instance and writes each one as <id>.eml inside the user-supplied output directory. The message ID field is taken verbatim from the JSON response of the remote server and concatenated into the output path with path.Join, which silently normalizes `..` segments. A malicious HTTP server impersonating Mailpit can therefore make mailpit dump write attacker-controlled bytes to any path the running user can write, fully outside the intended output directory. Version 1.30.0 contains a patch.
Which versions are affected by CVE-2026-45711?
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 | 1.30.0 |
github.com/axllent/mailpit Go | All versions | 1.30.0 |
github.com/axllent/mailpit Go | All versions | 1.30.0 |
Products include Axllent Mailpit.
How do I fix CVE-2026-45711?
Upgrade github.com/axllent/mailpit to 1.30.0 or later.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-45711 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-45711 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-2026-45712 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
- CVE-2026-27808 Mailpit is Vulnerable to Server-Side Request Forgery (SSRF) via Link Check API
Sources
Also known as GHSA-qx5x-85p8-vg4j, GO-2026-5599.