GHSA-77jf-fjjf-xcww is a medium-severity (CVSS 5.9) Broken Cryptographic Algorithm vulnerability in openpgp. 1 public exploit reference exists, so weaponization risk is real. O3 Security confirms whether GHSA-77jf-fjjf-xcww is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Invalid Curve Attack in openpgp
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, a proxy for how much of the ecosystem is exposed.
openpgpnpmDescription
Versions of openpgp prior to 4.3.0 are vulnerable to an Invalid Curve Attack. The package's implementation of ECDH fails to verify the validity of the communication partner's public key. The package calculates the resulting key secret based on an altered curve instead of the specified elliptic curve. Attackers may exfiltrate the victim's private key by choosing the altered curve. An attack requires the attacker being able to initiate message decryption and record the result. Furthermore the victim's key must offer an ECDH public key.
Recommendation
Upgrade to version 4.3.0 or later.
If you are upgrading from a version <4.0.0 it is highly recommended to read the High-Level API Changes section of the openpgp 4.0.0 release: https://github.com/openpgpjs/openpgpjs/releases/tag/v4.0.0
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | openpgp | all versions | 4.3.0 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for openpgp. 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 openpgp to 4.3.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-77jf-fjjf-xcww 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-77jf-fjjf-xcww 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-77jf-fjjf-xcww. 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-77jf-fjjf-xcww in your dependencies?
O3 detects GHSA-77jf-fjjf-xcww across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.