# CVE-2026-85393: node-forge RSA signature forgery via ASN.1 parsing bypass

Source: https://junglewise.ai/threats/cve-2026-85393-node-forge-rsa-signature-forgery-via-asn-1-parsing-bypass  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-03. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-85393 · Severity: high · CVSS 7.5 · Published 2026-09-03

node-forge is a JavaScript cryptography library used to verify digital signatures on documents and communications. A flaw in RSA signature verification allows attackers to forge valid signatures for arbitrary messages when using low-exponent RSA keys (exponent=3), bypassing security checks that would be caught by standard cryptographic implementations like OpenSSL. This could enable unauthorized access to signed documents or impersonation of legitimate signers.

Technologies: [node-forge (npm)](https://junglewise.ai/threats/technologies/node-forge). Vendors: [npm](https://junglewise.ai/threats/vendors/npm).

## Quick answers

**Is CVE-2026-85393 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-85393 being exploited in the wild.

**How severe is CVE-2026-85393?** High severity, with a CVSS score of 7.5, published 3 September 2026.

**Which products and versions are affected?** node-forge (npm) <= 1.4.0.

**Is there a fix for CVE-2026-85393?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-85393 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-85393?** Check whether you run node-forge (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability exists in node-forge's RSA PKCS#1 v1.5 signature verification logic (lib/rsa.js). The _parseAllDigestBytes option guarantees all ASN.1 bytes are parsed but does not enforce that the parsed structure matches the minimal canonical DigestInfo shape required by RFC 8017. Attackers can embed attacker-controlled additional ASN.1 content (garbage bytes) within the DigestAlgorithm sequence to construct forged signatures that pass forge verification but fail OpenSSL verification. Additionally, forge does not validate the minimum 8 bytes of padding (PS) specified in PKCS#1 v1.5, further reducing the difficulty of constructing Bleichenbacher-style forgeries. The issue is triggered when verifying signatures with default scheme (RSASSA-PKCS1-v1_5) on low-exponent RSA keys; no user interaction or authentication is required.

## Affected products

- Digital Bazaar node-forge through 1.4.0

## Identifiers

- CVE-2026-85393
- GHSA-86w9-cpqp-85rv

## Timeline

- 2026-09-03: disclosed

## References

- [https://github.com/digitalbazaar/forge](https://github.com/digitalbazaar/forge)

## Related threats

- [Forge: Ed25519 signature verification accepts small-order public keys](https://junglewise.ai/threats/cve-2026-125335-forge-also-called-node-forge-is-a-native-implementation-of)
- [Forge TLS client crash on handshake record without session](https://junglewise.ai/threats/cve-2026-125334-forge-also-called-node-forge-is-a-native-implementation-of)
- [Forge HTTP ReDoS in response header parsing](https://junglewise.ai/threats/cve-2026-125333-forge-also-called-node-forge-is-a-native-implementation-of)
- [Forge TLS client crash on unsupported ServerHello compression](https://junglewise.ai/threats/cve-2026-125332-forge-also-called-node-forge-is-a-native-implementation-of)
- [Forge RSA PKCS#1 v1.5 signature forgery via non-canonical DigestInfo encoding](https://junglewise.ai/threats/cve-2026-119192-forge-rsa-pkcs-1-v1-5-signature-forgery-via-non-canonical)