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OpenAdvisories
High · 7.5 CVE-2022-39218 EUVD-2022-6780GHSA-cmr8-5w4c-44v8

Random number seed fixed during compilation

Published Sep 20, 2022 · Updated Apr 23, 2025 · Assigned by GitHub_M

Description

The JS Compute Runtime for Fastly's Compute@Edge platform provides the environment JavaScript is executed in when using the Compute@Edge JavaScript SDK. In versions prior to 0.5.3, the `Math.random` and `crypto.getRandomValues` methods fail to use sufficiently random values. The initial value to seed the PRNG (pseudorandom number generator) is baked-in to the final WebAssembly module, making the sequence of random values for that specific WebAssembly module predictable. An attacker can use the fixed seed to predict random numbers generated by these functions and bypass cryptographic security controls, for example to disclose sensitive data encrypted by functions that use these generators. The problem has been patched in version 0.5.3. No known workarounds exist.

Affected products

VendorProductAffectedFixed
fastly js-compute-runtime < 0.5.3 —

Affected packages

EcosystemPackageAffectedFixedRecord
npm @fastly/js-compute >= 0.4.0, < 0.5.3 0.5.3 GHSA-cmr8-5w4c-44v8

References