CVE-2026-45712

MEDIUM CVSS 3.1: 5.9 EPSS 0.25%
Updated Jul 28, 2026
Axllent
Parameter Value
CVSS 5.9 (MEDIUM)
Affected Versions before 1.30.0
Fixed In 1.30.0
Type CWE-362 (Race Condition), CWE-770 (Allocation Without Limits)
Vendor Axllent
Public PoC No

Mailpit is an email testing tool and API for developers. Prior to version 1.30.0, the screenshot/print proxy (/proxy?data=…) maintains a package-level assets map[string]MessageAssets cache, but reads the map without holding assetsMutex while a long-running cleanup goroutine and (re-entrant) CSS-rewriting code path concurrently write to it under the lock. When the unsynchronized read coincides with a synchronized write, Go's runtime raises fatal error: concurrent map read and map write — a runtime.throw that is not recoverable by http.Server's handler-panic recover.

The whole Mailpit process exits, taking the SMTP, POP3 and HTTP listeners down with it. Version 1.30.0 contains a patch.

Attack Parameters

Attack Vector
Network
Can be exploited remotely
Attack Complexity
High
Difficult to exploit
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed

Impact Assessment

Confidentiality
None
No data leak
Integrity
None
No data modification
Availability
High
Complete denial of service

CVSS Vector v3.1

Vulnerable Products 1

Configuration From (including) Up to (excluding)
Axllent Mailpit
cpe:2.3:a:axllent:mailpit:*:*:*:*:*:*:*:*
1.30.0