Overview
About vulnerability
A flaw in Node.js HMAC verification uses a non-constant-time comparison when validating user-provided signatures, potentially leaking timing information proportional to the number of matching bytes. Under certain threat models where high-resolution timing measurements are possible, this behavior could be exploited as a timing oracle to infer HMAC values.
Node.js already provides timing-safe comparison primitives used elsewhere in the codebase, indicating this is an oversight rather than an intentional design decision.
This vulnerability affects 20.x, 22.x, 24.x, and 25.x.
Details
- Affected product:
- AlmaLinux 9.2 ESU , Alpine Linux 3.22 , Alpine Linux 3.23 , Debian 10 , Debian 11 , Debian 12 , Debian 13 , EL 10 , EL 7 , EL 8 , EL 9 , TuxCare 9.6 ESU , Ubuntu 18.04 , Ubuntu 20.04 , Ubuntu 22.04 , Ubuntu 24.04
- Affected packages:
- nodejs @ 23.11.1 (+61 more)
A flaw in Node.js HMAC verification uses a non-constant-time comparison when validating user-provided signatures, potentially leaking timing information proportional to the number of matching bytes. Under certain threat models where high-resolution timing measurements are possible, this behavior could be exploited as a timing oracle to infer HMAC values.
Node.js already provides timing-safe comparison primitives used elsewhere in the codebase, indicating this is an oversight rather than an intentional design decision.
This vulnerability affects 20.x, 22.x, 24.x, and 25.x.