Description
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.
Affected products
axllent: mailpit
References3
- github.com/axllent/mailpit/security/advisories/GHSA-w4vj-r5pg-3… ExploitVendor Advisory
- github.com/axllent/mailpit/security/advisories/GHSA-w4vj-r5pg-3… ExploitVendor Advisory
- github.com/axllent/mailpit/releases/tag/v1.30.0 Release Notes
Metrics
- CVSS 3.1
-
5.9
MEDIUM
Score source: CNA
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H - EPSS — exploit probability
- 0% percentile: 27 · as of 14 November 2026
- CWE
- CWE-362CWE-770
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