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
Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.
workerdnpmDescription
Impact
Prior to version v1.20230419.0, the FormData API implementation was subject to an integer overflow. If a FormData instance contained more than 2^31 elements, the forEach() method could end up reading from the wrong location in memory while iterating over elements. This would most likely lead to a segmentation fault, but could theoretically allow arbitrary undefined behavior.
In order for the bug to be exploitable, the process would need to be able to allocate 160GB of RAM. Due to this, the bug was never exploitable on the Cloudflare Workers platform, but could theoretically be exploitable on deployments of workerd running on machines with a huge amount of memory. Moreover, in order to be remotely exploited, an attacker would have to upload a single form-encoded HTTP request of at least tens of gigabytes in size. The application code would then have to use request.formData() to parse the request and formData.forEach() to iterate over this data. Due to these limitations, the exploitation likelihood was considered Low.
Patches
A fix that addresses this vulnerability has been released in version v1.20230419.0 and users are encouraged to update to the latest version available.
References
Release - https://github.com/cloudflare/workerd/releases/tag/v1.20230419.0
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | workerd | all versions | 1.20230419.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for workerd. 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 workerd to 1.20230419.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-8vx6-69vg-c46f 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-8vx6-69vg-c46f 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-8vx6-69vg-c46f. 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-8vx6-69vg-c46f in your dependencies?
O3 detects GHSA-8vx6-69vg-c46f across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.