GHSA-vchh-r53j-8mpw is a medium-severity (CVSS 4.3) Improper Input Validation vulnerability in github.com/fission/fission. O3 Security confirms whether GHSA-vchh-r53j-8mpw is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Fission: HTTPTrigger admission omits RelativeURL / Prefix validation; kubectl apply bypasses CLI checks
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.
How urgent is this, really
GHSA-vchh-r53j-8mpw plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 372,324 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
github.com/fission/fissionReal-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
HTTPTriggerSpec.Validate() validated Methods, FunctionReference, Host, IngressConfig, and CorsConfig, but silently skipped RelativeURL and Prefix. Those two fields were validated at the CLI level only
(pkg/fission-cli/cmd/httptrigger/create.go:83). The post-CRD-modernization webhook for HTTPTrigger was retired in favor of API-server CEL — and CEL had no rules on those fields either — so an HTTPTrigger created via kubectl apply or
a direct Kubernetes REST API call bypassed every URL-level check.
A tenant with HTTPTrigger create permission could therefore create triggers whose RelativeURL or Prefix:
- was empty (with both fields unset, the trigger has no URL),
- did not start with
/, - was exactly
/(claiming the entire router root), - contained
..traversal segments (e.g./api/../admin), - collided with router-owned routes:
/router-healthz,/readyz,/_version,/auth/login, - collided with the router-internal function prefix
/fission-function/<ns>/<name>.
Affected
- Project:
github.com/fission/fission - Versions: all versions through v1.24.0
- Audited commit:
647c141 - Component:
pkg/apis/core/v1/validation.go:HTTPTriggerSpec.Validate(and the missing CEL onHTTPTriggerSpec) - Configuration: default
Fix section (paste into the Fix / Patches field)
Fixed in v1.25.0 by:
- PR #3464 (commit
0deed6bf) — enforce the path-safety invariants at both admission layers so the API server's CEL evaluation and the Go-sideHTTPTriggerSpec.Validate()agree:- Three
+kubebuilder:validation:XValidationrules onHTTPTriggerSpec(the API server's CEL admission gate, regenerated intocrds/v1/fission.io_httptriggers.yaml):- at least one of
relativeurlorprefixmust be non-empty; relativeurl, when set, must start with/, must not be/, must contain no..segment, must not be in the reserved exact-path set, and must not start with/fission-function/;prefix, when set, the same rules guarded byhas(self.prefix).
- at least one of
validateTriggerPathhelper inpkg/apis/core/v1/validation.go, invoked fromHTTPTriggerSpec.Validate(), mirrors the CEL rules so the CLI's early rejection and the router reconciler's status-Condition path match what the API server admits.
- Three
Regression coverage: a new TestHTTPTriggerSpecValidate_Path table in pkg/apis/core/v1/validation_validators_test.go exercises every PoC case from the advisory plus literal ..-prefixed-segment positives that must remain allowed.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/fission/fission | all versions | 1.25.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/fission/fission. 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/fission/fission to 1.25.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-vchh-r53j-8mpw 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-vchh-r53j-8mpw 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-vchh-r53j-8mpw. 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-vchh-r53j-8mpw in your dependencies?
O3 detects GHSA-vchh-r53j-8mpw across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.