CVE-2026-33895 — Forge has signature forgery in Ed25519 due to missing S > L check

Description (CNA)

Forge (also called `node-forge`) is a native implementation of Transport Layer Security in JavaScript. Prior to version 1.4.0, Ed25519 signature verification accepts forged non-canonical signatures where the scalar S is not reduced modulo the group order (`S >= L`). A valid signature and its `S + L` variant both verify in forge, while Node.js `crypto.verify` (OpenSSL-backed) rejects the `S + L` variant, as defined by the specification. This class of signature malleability has been exploited in practice to bypass authentication and authorization logic (see CVE-2026-25793, CVE-2022-35961). Applications relying on signature uniqueness (i.e., dedup by signature bytes, replay tracking, signed-object canonicalization checks) may be bypassed. Version 1.4.0 patches the issue.

Affected (CNA)

Vendor / product	Versions
digitalbazaar / forge	affected < 1.4.0

CWE

CWE-347

References

ADP enrichment

CISA-ADP

No English description supplied.

https://github.com/digitalbazaar/forge/security/advisories/GHSA-q67f-28xg-22rw

redhat-SADP

A flaw was found in Forge (also called `node-forge`), a JavaScript library used for Transport Layer Security (TLS). The library's Ed25519 signature verification process does not correctly validate cryptographic signatures, allowing forged non-canonical signatures to be accepted. A remote attacker could exploit this signature malleability to bypass authentication and authorization logic. This vulnerability can also circumvent security checks in applications that rely on the uniqueness of cryptographic signatures for functions such as deduplication or preventing replay attacks.