CVE-2026-45712

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.

CVSS 3.1

5.9CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

0.3% chance of exploitation in the next 30 days; higher than 26% of CVEs (scores of 2026-10-25)

CWEs

CWE-362, CWE-770

Published

2026-07-20

Modified

2026-10-24

Record from

the NVD, synced 2026-10-25

Affected

• axllent:mailpit

Packages (OSV)

References

• https://github.com/axllent/mailpit/releases/tag/v1.30.0
• https://github.com/axllent/mailpit/security/advisories/GHSA-w4vj-r5pg-3722
• https://github.com/axllent/mailpit/security/advisories/GHSA-w4vj-r5pg-3722

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