SSWConsulting / SSWConsulting/SSW.MeetupMCP

Image uploadUrl is not pinned to HTTPS or a Meetup host

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Area: Backend Type: Bug
Dominant language
TypeScript
Stars
1
Forks
0
PR merge metrics
No merged PRs in 30d

Description

Summary

The upload URL returned by the photo-placeholder mutation is validated with z.url() at src/meetup/response-schemas.ts:146, and the server then PUTs local file bytes to whatever came back.

z.url() in Zod 4 accepts far more than intended. Confirmed accepted: file:///etc/passwd, http://localhost:8080/x, http://169.254.169.254/latest/meta-data/, ftp://x/y.

Impact

Low likelihood, since the response arrives over TLS from api.meetup.com and exploiting this requires a compromised Meetup API or TLS interception. Filed because the fix is a one-liner and the consequence is that local file contents get written to an attacker-chosen destination.

Suggested fix

Require the scheme to be https: and the host to end in a known Meetup or storage-provider suffix. Reject anything else with a meetup_api error before the PUT is issued.

Contributor guide

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First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start at src/meetup/response-schemas.ts:146 and trace the photo-placeholder mutation through the PUT that sends local file bytes. Confirm the accepted URL scheme and host suffixes, then verify invalid URLs produce a meetup_api error before the PUT is issued.

Written by the indexing model from the issue text.

Assessment

Tech stack
typescript
Domain
security
Issue type
Bug
Difficulty
2/5
Estimated time
1-3 hours
Activity status
Quiet
Clarity
Mostly clear
Newbie friendliness
72/100

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