How severe is GHSA-327c-qx3v-h673?

GHSA-327c-qx3v-h673 has a CVSS score of 9.8/10, rated CRITICAL. Immediate patching is strongly recommended.

Which packages are affected by GHSA-327c-qx3v-h673?

GHSA-327c-qx3v-h673 affects the following packages: hermes-engine (npm). Ecosystems affected: npm.

How do I fix GHSA-327c-qx3v-h673?

Update hermes-engine to 0.7.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-327c-qx3v-h673 is resolved across your whole dependency graph.

How do I detect GHSA-327c-qx3v-h673 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for hermes-engine. 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.

How do I mitigate GHSA-327c-qx3v-h673 if there is no patch (or I can't update yet)?

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 does O3 Security protect against GHSA-327c-qx3v-h673?

O3 pinpoints whether GHSA-327c-qx3v-h673 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is GHSA-327c-qx3v-h673 actively exploited in the wild?

No public exploit code has been indexed for GHSA-327c-qx3v-h673 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.

What is the EPSS score for GHSA-327c-qx3v-h673?

GHSA-327c-qx3v-h673 has an EPSS (Exploit Prediction Scoring System) score of 2.4%, placing it in the 82th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

When was GHSA-327c-qx3v-h673 published, and has it been updated?

GHSA-327c-qx3v-h673 was published on May 24, 2022 and was last updated on November 8, 2023. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

GHSA-327c-qx3v-h673: hermes-engine Remote Code Execution (Criti…

EPSS Exploitation Probability

via FIRST.org ↗

2.4%probability of exploitation in next 30 days

Lower Risk82th percentile+1.01%

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

1 pkg affected

Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.

hermes-enginenpm

177Kdownloads / week

Description

A logic vulnerability when handling the SaveGeneratorLong instruction in Facebook Hermes prior to commit b2021df620824627f5a8c96615edbd1eb7fdddfc allows attackers to potentially read out of bounds or theoretically execute arbitrary code via crafted JavaScript. Note that this is only exploitable if the application using Hermes permits evaluation of untrusted JavaScript. Hence, most React Native applications are not affected.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`hermes-engine`	all versions	0.7.2

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for hermes-engine. 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 hermes-engine to 0.7.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-327c-qx3v-h673 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-327c-qx3v-h673 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-327c-qx3v-h673. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

A logic vulnerability when handling the SaveGeneratorLong instruction in Facebook Hermes prior to commit b2021df620824627f5a8c96615edbd1eb7fdddfc allows attackers to potentially read out of bounds or theoretically execute arbitrary code via crafted JavaScript. Note that this is only exploitable if the application using Hermes permits evaluation of untrusted JavaScript. Hence, most React Native applications are not affected.

O3 Security · Impact-Aware SCA

Is GHSA-327c-qx3v-h673 in your dependencies?

O3 detects GHSA-327c-qx3v-h673 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works

GHSA-327c-qx3v-h673