CVE-2026-33894: Forge has signature forgery in RSA-PKCS due to ASN.1 extra field
Forge (also called `node-forge`) is a native implementation of Transport Layer Security in JavaScript. Prior to version 1.4.0, RSASSA PKCS#1 v1.5 signature verification accepts forged signatures for low public exponent keys (e=3). Attackers can forge signatures by stuffing “garbage” bytes within the ASN structure in order to construct a signature that passes verification, enabling Bleichenbacher style forgery. This issue is similar to CVE-2022-24771, but adds bytes in an addition field within the ASN structure, rather than outside of it. Additionally, forge does not validate that signatures include a minimum of 8 bytes of padding as defined by the specification, providing attackers additional space to construct Bleichenbacher forgeries. Version 1.4.0 patches the issue.
Metrics
- CVSS v3.1
- 7.5
- Severity
- HIGH
- Fixed in
- —
- Affected Products
- 1
- digitalbazaar / forge< 1.4.0
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N- https://github.com/digitalbazaar/forge/security/advisories/GHSA-ppp5-5v6c-4jwp
- https://github.com/digitalbazaar/forge/security/advisories/GHSA-ppp5-5v6c-4jwp
- https://datatracker.ietf.org/doc/html/rfc2313#section-8
- https://mailarchive.ietf.org/arch/msg/openpgp/5rnE9ZRN1AokBVj3VqblGlP63QE
- https://www.rfc-editor.org/rfc/rfc8017.html