CVE-2026-45712 Mailpit: Concurrent map read & write in proxy CSS rewriter - remote unauth crash (fatal error: concurrent map read and map write)

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 mapstringMessageAssets cache, but reads the map without holding assetsMutex while a long-running cleanup goroutine and re-entrant CSS-rewriti...

Race Condition

Overview Affected versions of this package are vulnerable to Race Condition through the proxyCSSRewriter process. An attacker can cause the application to crash by triggering concurrent access to shared resources, resulting in a denial of service. Remediation Upgrade...

GO-2026-5689 Mailpit: Concurrent map read & write in proxy CSS rewriter - remote unauth crash (fatal error: concurrent map read and map write) in github.com/axllent/mailpit

Mailpit: Concurrent map read & write in proxy CSS rewriter - remote unauth crash fatal error: concurrent map read and map write in github.com/axllent/mailpit...

Mailpit: Concurrent map read & write in proxy CSS rewriter - remote unauth crash (fatal error: concurrent map read and map write)

Summary The screenshot/print proxy /proxy?data=… maintains a package-level assets mapstringMessageAssets 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...