How severe is GHSA-4c5f-9mj4-m247?

No CVSS score has been assigned to GHSA-4c5f-9mj4-m247 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-4c5f-9mj4-m247?

GHSA-4c5f-9mj4-m247 affects the following packages: github.com/open-feature/flagd/core (Go), github.com/open-feature/flagd/flagd-proxy (Go), github.com/open-feature/flagd/flagd (Go). Ecosystems affected: Go.

How do I fix GHSA-4c5f-9mj4-m247?

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.

How do I detect GHSA-4c5f-9mj4-m247 in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/open-feature/flagd/core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate GHSA-4c5f-9mj4-m247 if there is no patch (or I can't update yet)?

Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Is GHSA-4c5f-9mj4-m247 actively exploited in the wild?

No public exploit code has been indexed for GHSA-4c5f-9mj4-m247 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

When was GHSA-4c5f-9mj4-m247 published, and has it been updated?

GHSA-4c5f-9mj4-m247 was published on January 5, 2026 and was last updated on February 3, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹 Go

Not in CISA KEV

flagd: Multiple Go Runtime CVEs Impact Security and AvailabilityGHSA-4c5f-9mj4-m247

Fix: open-feature/flagd#1840

GHSA-4c5f-9mj4-m247 is a security vulnerability in github.com/open-feature/flagd/core. A fix is available for github.com/open-feature/flagd/core — see the affected versions and patch details below.

Also known asGO-2026-4279

Published

Jan 5, 2026

Updated

Feb 3, 2026

Affected

3 pkgs

Patched

3 / 3

Exploits

None indexed

Exploitation data as of Feb 3, 2026 · OSV.dev, FIRST.org (EPSS)

Real-World Exposure

3 pkgs affected

🐹github.com/open-feature/flagd/core🐹github.com/open-feature/flagd/flagd-proxy🐹github.com/open-feature/flagd/flagd

Real-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

3 total 3 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/open-feature/flagd/core`	all versions	0.13.1`go get github.com/open-feature/flagd/core@v0.13.1`
🐹Go	`github.com/open-feature/flagd/flagd-proxy`	all versions	0.8.2`go get github.com/open-feature/flagd/flagd-proxy@v0.8.2`
🐹Go	`github.com/open-feature/flagd/flagd`	all versions	0.13.1`go get github.com/open-feature/flagd/flagd@v0.13.1`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/open-feature/flagd/core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
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
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Frequently Asked Questions

### 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), po

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