CVE-2026-85393
Attackers can embed garbage bytes inside the DigestAlgorithm sequence to forge valid signatures for arbitrary messages using low-exponent RSA keys.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.20%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
node-forge through 1.4.0 fails to validate element count in nested DigestAlgorithm sequences during RSA PKCS#1 v1.5 signature verification. Attackers can embed garbage bytes inside the DigestAlgorithm sequence to forge valid signatures for arbitrary messages using low-exponent RSA keys. This is an incomplete fix for CVE-2026-33894.
- CVSS 4.0
- 8.7 HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 0.20% probability · 10th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-347
- Source
- disclosure@vulncheck.com
References
- https://github.com/advisories/GHSA-ppp5-5v6c-4jwp
- https://github.com/digitalbazaar/forge
- https://github.com/digitalbazaar/forge/blob/v1.4.0/lib/asn1.js
- https://github.com/digitalbazaar/forge/blob/v1.4.0/lib/rsa.js
- https://github.com/digitalbazaar/forge/issues/1149
- https://www.vulncheck.com/advisories/node-forge-through-1.4.0-rsa-pkcs-1-1.5-signature-forgery-via-nested-digestalgorithm-padding
- https://github.com/advisories/GHSA-ppp5-5v6c-4jwp
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.