Forge (node-forge) RSASSA PKCS#1 v1.5 forgery e=3 v<1.4
CVE-2026-33894 Published on March 27, 2026
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.
Vulnerability Analysis
CVE-2026-33894 is exploitable with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. An automatable proof of concept (POC) exploit exists. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality, a high impact on integrity, and no impact on availability.
Weakness Types
Improper Verification of Cryptographic Signature
The software does not verify, or incorrectly verifies, the cryptographic signature for data.
Improper Input Validation
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
Products Associated with CVE-2026-33894
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Affected Versions
digitalbazaar forge:- Version < 1.4.0 is affected.
- Version 0:2.5.20260422-3.el8ap and below * is unaffected.
- Version 0:2.5.20260422-3.el9ap and below * is unaffected.
- Version 1782839279 and below * is unaffected.
- Version 1776784286 and below * is unaffected.
- Version 1777903262 and below * is unaffected.
- Version 1779822261 and below * is unaffected.
- Version 1779811412 and below * is unaffected.
- Version 1779689392 and below * is unaffected.
- Version 1780891395 and below * is unaffected.
- Version 1779204086 and below * is unaffected.
- Version 1779922205 and below * is unaffected.
- Version 1779811473 and below * is unaffected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.