GHSA-9c5w-9q3f-3hv7
HIGHMinder's GitHub Webhook Handler vulnerable to DoS from un-validated requests
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
github.com/stacklok/minderReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
Minder's HandleGithubWebhook is susceptible to a denial of service attack from an untrusted HTTP request. The vulnerability exists before the request has been validated, and as such the request is still untrusted at the point of failure. This allows an attacker with the ability to send requests to HandleGithubWebhook to crash the Minder controlplane and deny other users from using it.
One of the first things that HandleGithubWebhook does is to validate the payload signature. This is done by way of the internal helper validatePayloadSignature:
validatePayloadSignature generates a reader from the incoming request by way of the internal helper readerFromRequest:
To create a reader from the incoming request, readerFromRequest first reads the request body entirely into memory on line 368:
This is a vulnerability, since an HTTP request with a large body can exhaust the memory of the machine running Minder and cause the Go runtime to crash Minder.
Note that this occurs before Minder has validated the request, and as such, the request is still untrusted.
To test this out, we can use the existing TestHandleWebHookRepository unit test and modify the HTTP request body to be large.
To do that, change these lines:
... to these lines:
packageJson, err := json.Marshal(event)
require.NoError(t, err, "failed to marshal package event")
maliciousBody := strings.NewReader(strings.Repeat("1337", 1000000000))
maliciousBodyReader := io.MultiReader(maliciousBody, maliciousBody, maliciousBody, maliciousBody, maliciousBody)
_ = packageJson
client := &http.Client{}
req, err := http.NewRequest("POST", fmt.Sprintf("http://%s", addr), maliciousBodyReader)
require.NoError(t, err, "failed to create request")
Then run the unit test again. WARNING, SAVE ALL WORK BEFORE DOING THIS.
On my local machine, this causes the machine to freeze, and Go finally performs a sigkill:
signal: killed
FAIL github.com/stacklok/minder/internal/controlplane 30.759s
FAIL
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/stacklok/minder | all versions | 0.0.48 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/stacklok/minder. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update github.com/stacklok/minder to 0.0.48 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-9c5w-9q3f-3hv7 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-9c5w-9q3f-3hv7 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-9c5w-9q3f-3hv7. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-9c5w-9q3f-3hv7 in your dependencies?
O3 detects GHSA-9c5w-9q3f-3hv7 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.