How severe is GHSA-cmr8-5w4c-44v8?

GHSA-cmr8-5w4c-44v8 has a CVSS score of 7.5/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by GHSA-cmr8-5w4c-44v8?

GHSA-cmr8-5w4c-44v8 affects the following packages: @fastly/js-compute (npm). Ecosystems affected: npm.

How do I fix GHSA-cmr8-5w4c-44v8?

Update @fastly/js-compute to 0.5.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-cmr8-5w4c-44v8 is resolved across your whole dependency graph.

How do I detect GHSA-cmr8-5w4c-44v8 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @fastly/js-compute, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate GHSA-cmr8-5w4c-44v8 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.

Is GHSA-cmr8-5w4c-44v8 actively exploited in the wild?

No public exploit code has been indexed for GHSA-cmr8-5w4c-44v8 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-cmr8-5w4c-44v8?

GHSA-cmr8-5w4c-44v8 has an EPSS (Exploit Prediction Scoring System) score of 0.9%, placing it in the 61th 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.

What type of vulnerability is GHSA-cmr8-5w4c-44v8?

GHSA-cmr8-5w4c-44v8 is classified as CWE-335 (CWE-335). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-cmr8-5w4c-44v8 published, and has it been updated?

GHSA-cmr8-5w4c-44v8 was published on September 20, 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.

📦

📦 npm

Not in CISA KEV

HIGH severity

Fastly Compute@Edge JS Runtime has fixed random number seed during compilationGHSA-cmr8-5w4c-44v8

HIGHFix: fastly/js-compute-runtime@65524ff

GHSA-cmr8-5w4c-44v8 is a high-severity (CVSS 7.5) CWE-335 vulnerability in @fastly/js-compute. A fix is available for @fastly/js-compute — see the affected versions and patch details below.

Also known asCVE-2022-39218

Published

Sep 20, 2022

Updated

Nov 8, 2023

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 7, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for GHSA-cmr8-5w4c-44v8.

EPSS Exploitation Probability

via FIRST.org ↗

0.9%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs61th percentile — riskier than 61% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

16other npm packages depend on this — each one inherits the vulnerability until it's patched upstream

@fastly/js-computenpm

215Kdownloads / week

Description

Impact

Math.random and crypto.getRandomValues methods failed to use sufficiently random values. The initial value to seed the CSPRNG (cryptographically secure pseudorandom number generator) was baked-in to the final WebAssembly module meaning the sequence of numbers generated was predictable for that specific WebAssembly module. An attacker with access to that same WebAssembly module that calls the affected methods could use the fixed seed to predict random numbers generated by these functions. This information could be used to bypass cryptographic security controls, for example to disclose sensitive data encrypted by functions that use these generators.

Patches

The problem has been fixed in version 0.5.3.

Corrected Math.random and crypto.getRandomValues methods to always use sufficiently random values. The previous versions would use a CSPRNG (cryptographically secure pseudorandom number generator) which we would seed with a random value. However, due to our use of Wizer, the initial value to seed the CSPRNG was baked-in to the final WebAssembly module meaning the sequence of numbers generated was predictable for that specific WebAssembly module. The new implementations of both Math.random and crypto.getRandomValues do not use a CSPRNG and instead pull random values from WASI (WebAssembly System Interface) libc’s random_get function, which is always a sufficiently random value.

Workarounds

There are no workarounds, you must upgrade to version 0.5.3 or later.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`@fastly/js-compute`	≥ 0.4.0&&< 0.5.3	0.5.3`npm install @fastly/js-compute@0.5.3`

Affected Products

1 product · 1 configurations

Application

js-computefastly

< 0.5.3

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @fastly/js-compute, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update @fastly/js-compute to 0.5.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-cmr8-5w4c-44v8 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.

Frequently Asked Questions

### Impact `Math.random` and `crypto.getRandomValues` methods failed to use sufficiently random values. The initial value to seed the CSPRNG (cryptographically secure pseudorandom number generator) was baked-in to the final WebAssembly module meaning the sequence of numbers generated was predictable for that specific WebAssembly module. An attacker with access to that same WebAssembly module that calls the affected methods could use the fixed seed to predict random numbers generated by these functions. This information could be used to bypass cryptographic security controls, for example to di