vulnerability / NVI-00014115 / Revision 1
Mailpit: Thumbnail generation decodes unbounded image dimensions before scaling
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.
7.5 high
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<= 1.30.3
## Summary Mailpit's thumbnail endpoint decodes attacker-supplied image attachments into a full raster before checking any decoded-pixel, dimension, or memory budget. A remote client that can store an email and reach the default web API can supply a compact high-dimension image, then request `/api/v1/message/{id}/part/{partID}/thumb` to force server-side memory and CPU work far larger than the encoded attachment size before Mailpit returns a 180x120 thumbnail. ## Technical Details The route is registered as `GET /api/v1/message/{id}/part/{partID}/thumb` in `server/server.go`. The handler in `server/apiv1/thumbnails.go` loads the requested attachment and accepts any part whose content type begins with `image/`: ```go a, err := storage.GetAttachmentPart(id, partID) // ... if !strings.HasPrefix(a.ContentType, "image/") { blankImage(a, w) return } buf := bytes.NewBuffer(a.Content) img, err := imaging.Decode(buf, imaging.AutoOrientation(true)) ``` `storage.GetAttachmentPart()` reparses the stored raw email and returns the matching attacker-supplied attachment bytes. `Thumbnail()` then calls `imaging.Decode()` before any check on declared dimensions or estimated decoded byt
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-75mr-qw9x-3r39 ↗
GitHub Advisory Database · vendor advisory
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Public revision history
Only published revisions appear here. Routine fetches do not create a material-change event.
- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.