GHSA-4c5f-9mj4-m247
flagd: Multiple Go Runtime CVEs Impact Security and Availability
Blast Radius
github.com/open-feature/flagd/core🐹github.com/open-feature/flagd/flagd-proxy🐹github.com/open-feature/flagd/flagdReal-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
Summary
In 2025, several vulnerabilities in the Go Standard Library were disclosed, impacting Go-based applications like flagd (the evaluation engine for OpenFeature). These CVEs primarily focus on Denial of Service (DoS) through resource exhaustion and Race Conditions in database handling.
| CVE ID | Impacted Package | Severity | Description & Impact on flagd |
|---|---|---|---|
| CVE-2025-47907 | database/sql | 7.0 (High) | Race Condition: Canceling a query during a Scan call can return data from the wrong query. Critical if flagd uses SQL-based sync providers (e.g., Postgres), potentially leading to incorrect flag configurations. |
| CVE-2025-61725 | net/mail | 7.5 (High) | DoS: Inefficient complexity in ParseAddress. Attackers can provide crafted email strings with large domain literals to exhaust CPU if flagd parses email-formatted metadata. |
| CVE-2025-61723 | encoding/pem | 7.5 (High) | DoS: Quadratic complexity when parsing invalid PEM inputs. Relevant if flagd loads TLS certificates or keys via PEM files from untrusted sources. |
| CVE-2025-61729 | crypto/x509 | 7.5 (High) | Resource Exhaustion: HostnameError.Error() lacks string concatenation limits. A malicious TLS certificate with thousands of hostnames could crash flagd during connection handshakes. |
| CVE-2025-58188 | net/http | Medium | Request Smuggling: Improper header handling in HTTP/1.1. Could allow attackers to bypass security filters positioned in front of flagd sync or evaluation APIs. |
| CVE-2025-58187 | archive/zip | Medium | DoS: Improper validation of malformed ZIP archives. Impacts flagd if configured to fetch and unpack zipped configuration bundles from remote providers. |
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/open-feature/flagd/core | all versions | 0.13.1 |
| 🐹Go | github.com/open-feature/flagd/flagd-proxy | all versions | 0.8.2 |
| 🐹Go | github.com/open-feature/flagd/flagd | all versions | 0.13.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/open-feature/flagd/core. 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/open-feature/flagd/core to 0.13.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-4c5f-9mj4-m247 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-4c5f-9mj4-m247 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-4c5f-9mj4-m247. 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-4c5f-9mj4-m247 in your dependencies?
O3 detects GHSA-4c5f-9mj4-m247 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.