GHSA-77gc-fj98-665h is a high-severity (CVSS 7.5) CWE-284 vulnerability in gopkg.in/square/go-jose.v1. A fix is available for gopkg.in/square/go-jose.v1 — see the affected versions and patch details below.
Go JOSE Signature Validation Bypass
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-77gc-fj98-665h 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 378,156 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
gopkg.in/square/go-jose.v1Real-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
go-jose before 1.0.4 suffers from multiple signatures exploitation. The go-jose library supports messages with multiple signatures. However, when validating a signed message the API did not indicate which signature was valid, which could potentially lead to confusion. For example, users of the library might mistakenly read protected header values from an attached signature that was different from the one originally validated.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | gopkg.in/square/go-jose.v1 | all versions | 1.1.0go get gopkg.in/square/go-jose.v1@v1.1.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for gopkg.in/square/go-jose.v1, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update gopkg.in/square/go-jose.v1 to 1.1.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-77gc-fj98-665h 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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-77gc-fj98-665h can be triaged on real exposure rather than presence alone.
Tailored to GHSA-77gc-fj98-665h. 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-77gc-fj98-665h in your dependencies?
O3 Security finds GHSA-77gc-fj98-665h across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.