vulnerability / NVI-00018609 / Revision 1
Bunsink has an SSRF bypass in `validate_webhook_url`
GitHub lists this reviewed advisory for bugsink. 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
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4.3 medium
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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.
bugsink
source listed<= 2.1.2
## Summary Bugsink’s webhook URL validation in versions 2.1.2 and earlier could be (partially) bypassed because of a mismatch in URL parsing. In some malformed URLs, Python’s standard URL parser (urllib) and the HTTP client stack (requests / urllib3) do not agree on which host is actually being targeted. That could allow a webhook URL to pass Bugsink’s outbound-host checks while the actual HTTP request is sent somewhere else. ## Impact This issue affects Bugsink’s outbound webhook integrations. An attacker who can supply or influence a webhook URL may be able to make Bugsink send an outbound HTTP POST request to a host that should have been blocked by the webhook validation logic, including loopback, private, or otherwise non-allowlisted destinations. The practical impact is limited: - this is an outbound webhook SSRF issue, not a general-purpose proxy - Bugsink does not follow redirects for these webhook requests - the request shape is constrained by how the malformed URL is normalized by the HTTP client - this does not give arbitrary control over every possible request path In other words, this is a real validation bypass, but it is narrower than a full arbitrary-request
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.
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04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
05 / Provenance
Sources you can inspect
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- GHSA-fp53-qcf8-2xx2 ↗
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Public revision history
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- Revision 1 ·
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