CyberRota Analysis
AI-GeneratedMailpit's SMTP server and HTTP API are vulnerable due to an unbounded maximum payload size, allowing unauthenticated attackers to send excessively large messages, which can lead to significant RAM consumption and potential out-of-memory (OOM) crashes. This vulnerability poses a high risk to developers using Mailpit for email testing, particularly those with network-accessible instances. Users should prioritize upgrading to version 1.30.0 to mitigate this risk.
Public Exploit Signal
A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.
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Original NVD Description
Mailpit is an email testing tool and API for developers. Prior to version 1.30.0, the Mailpit SMTP server has a Server.MaxSize int field that controls the maximum allowed DATA payload size, but the field is never assigned anywhere outside test code, leaving it at Go's zero value (0 ⇒ "no limit"). The same applies to the HTTP /api/v1/send endpoint, whose request body is decoded with json.NewDecoder(r.Body) and no http.MaxBytesReader. Because Mailpit's default listeners bind [::]:1025 (SMTP) and [::]:8025 (HTTP), with no authentication required on either, a single network-reachable attacker can push an arbitrarily large message into Mailpit and watch RAM consumption spike with a ~7-10× amplification factor (raw frame → enmime envelope tree → search-text index → zstd-encoded write to SQLite). Repeating the attack — or running it concurrently from multiple connections — drives the process to OOM-kill. Version 1.30.0 contains a patch.
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