Mailpit is an email testing tool and API for developers. Prior to version 1.30.1, the fix for GHSA-fpxj-m5q8-fphw (CVE-2026-45710, "Mailpit: Set a default 50MB p/m limit to prevent DoS via unlimited SMTP DATA and /api/v1/send body sizes") wrapped only `POST /api/v1/send` with `http.MaxBytesReader`. The four other Mailpit JSON-body API endpoints `PUT /api/v1/messages` (SetReadStatus), `DELETE /api/v1/messages` (DeleteMessages), `PUT /api/v1/tags` (SetMessageTags), and `POST /api/v1/message/{id}/release` (ReleaseMessage) still call `json.NewDecoder(r.Body)` directly with no body-size cap and remain reachable unauthenticated in the default `docker run axllent/mailpit:latest` deploy. An unauthenticated remote attacker can post a multi-million-element `IDs` slice and drive RSS from ~25 MiB baseline to ~450 MiB per 16 MB request body. Repeating across multiple connections accumulates the same per-request amplification per process. Version 1.30.1 contains a patch.
Fix
Patch, vendor advisory and mitigation references on NVD 1
- https://github.com/axllent/mailpit/security/advisories/GHSA-28pq-6qxg-wg5r Exploit, Vendor Advisory
Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.
Change history 1
- First seenCVSS 5.3 · axllentNVD modified 2026-10-24 20:10
Affected (CPE criteria) 1
cpe:2.3:a:axllent:mailpit:*:*:*:*:*:*:*:*
References 2
- https://github.com/axllent/mailpit/releases/tag/v1.30.1 Release Notes
- https://github.com/axllent/mailpit/security/advisories/GHSA-28pq-6qxg-wg5r Exploit, Vendor Advisory