CVE-2026-33895
Forge has signature forgery in Ed25519 due to missing S > L check
- State
- Published
- Severity
- 7.5 High
- Published
- Mar 27, 2026
- Updated
- Sep 4, 2026
- Reserved
- Mar 24, 2026
Description
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 7.5 High | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N | GitHub_M |
| 3.1 | 7.5 High | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N | redhat-SADP |
Weaknesses
- CWE-347 Improper Verification of Cryptographic Signature
Affected Products
| Product | Versions |
|---|---|
forgedigitalbazaar |
|
References
- https://github.com/digitalbazaar/forge/security/advisories/GHSA-q67f-28xg-22rw
- https://github.com/digitalbazaar/forge/commit/bdecf11571c9f1a487cc0fe72fe78ff6dfa96b85
- https://datatracker.ietf.org/doc/html/rfc8032#section-8.4
- https://access.redhat.com/security/cve/CVE-2026-33895vdb-entry
- RHBZ#2452457issue-tracking
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33895.json
- https://access.redhat.com/errata/RHSA-2026:24761vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:34342vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:9742vendor-advisory
- https://access.redhat.com/errata/RHSA-2026:13826vendor-advisory
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