vulnerability / NVI-00014121 / Revision 1
Mailpit: Sibling-endpoint memory-exhaustion DoS via unbounded JSON body on /api/v1/messages, /api/v1/tags, and /api/v1/message/{id}/release (incomplete fix of GHSA-fpxj-m5q8-fphw)
GitHub lists this reviewed advisory for github.com/axllent/mailpit. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
5.3 medium
GitHub source severity; exploitability and local consequence require separate evidence.
As of · GitHub Advisory Database
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
github.com/axllent/mailpit
source listed<= 1.30.0
### Summary 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. ### Affected versions - Mailpit at HEAD `67a7ca83ff759082d2b86dda07eb5bb3dad404e0` (v1.30.0, 2026-05-14). - All versions `<= v1.30.0` (the release that shipped the GHSA-fpxj fix). Versions `< v1.30.0` are vulnerable to the original GHSA-fpxj on `/api/v1/send`; version `v1.30.0` carries the sibling-endpoint gap described here
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. GitHub Advisory Database
A fixed release is not deployment evidence.
Check current vendor support and compatibility. After making a change, verify the deployed build and relevant runtime conditions. Keep the evidence, owner and time. An updated lockfile alone does not prove what is running.
04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
05 / Provenance
Sources you can inspect
Each assertion retains its source. Mirrored records may repeat one underlying publisher; additional links are not independent corroboration.
- GHSA-28pq-6qxg-wg5r ↗
GitHub Advisory Database · vendor advisory
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Public revision history
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- Revision 1 ·
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