CVE-2026-22689 Mailpit is vulnerable to Cross-Site WebSocket Hijacking (CSWSH) allowing unauthenticated access to emails
An attacker can hijack WebSocket connections to read sensitive email data from a local Mailpit instance via a malicious website.
- 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-2026-22689?
CVE-2026-22689 is a medium-severity vulnerability in axllent mailpit, published on 10 Jan 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 1.28.2, the Mailpit WebSocket server is configured to accept connections from any origin. This lack of Origin header validation introduces a Cross-Site WebSocket Hijacking (CSWSH) vulnerability. An attacker can host a malicious website that, when visited by a developer running Mailpit locally, establishes a WebSocket connection to the victim's Mailpit instance (default ws://localhost:8025). This allows the attacker to intercept sensitive data such as email contents, headers, and server statistics in real-time. This issue has been patched in version 1.28.2.
Weakness: CWE-1385
Which versions are affected by CVE-2026-22689?
5 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 | 0.0.0-20260110031614 |
github.com/axllent/mailpit Go | All versions | 0.0.0-20260110031614 |
github.com/axllent/mailpit Go | From 1.2.6 | 1.28.2 |
github.com/axllent/mailpit Go | From 1.2.6 | 1.28.2 |
github.com/axllent/mailpit Go | From 1.2.6 | 1.28.2 |
Products include Axllent Mailpit.
How do I fix CVE-2026-22689?
Upgrade github.com/axllent/mailpit to a fixed version for your release line: 0.0.0-20260110031614 or 1.28.2.
Is CVE-2026-22689 being exploited?
There is no known exploitation of CVE-2026-22689 in the wild and no public exploit code.
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-2026-45711 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
- CVE-2026-27808 Mailpit is Vulnerable to Server-Side Request Forgery (SSRF) via Link Check API
Sources
Also known as GHSA-524m-q5m7-79mm, GO-2026-4310.