Fix RSA PKCS#1 v1.5 forgery via nested DigestAlgorithm garbage - #1152
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Krysthyan wants to merge 1 commit into
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Fix RSA PKCS#1 v1.5 forgery via nested DigestAlgorithm garbage#1152Krysthyan wants to merge 1 commit into
Krysthyan wants to merge 1 commit into
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Require DigestAlgorithm SEQUENCE element count (OID + optional NULL) so asn1.validate cannot ignore interior padding that bypasses CVE-2026-33894. Co-authored-by: Cursor <cursoragent@cursor.com>
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Hi @Krysthyan I can get behind this solution instead of the one I've made, since it's simpler and does not introduce the potential overhead of adding captureAsn1 to check the same thing. Have you run the rest of the suites just in case they also pass? @davidlehn can you check this? The CVE is blocking several pipelines as much as I can see in the mentions of #1149 I will close my PR in favor of this one. |
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Summary
obj.value.length === 2on the outerDigestInfoSEQUENCE.asn1.validatestill ignores extra children inside the nestedDigestAlgorithmSEQUENCE, so attackers can stuff ~314 garbage bytes there and forge signatures for low public exponent keys (e.g.e=3).DigestAlgorithmSEQUENCE to contain only the OID plus an optional NULL (same pattern as the outer length check).Test plan
DigestAlgorithmchildren[OID, NULL, garbage]verified astruebefore the change; throws invalid DigestInfo after.should check nested DigestAlgorithm element countintests/unit/rsa.js.npx mocha tests/unit/rsa.js— 101 passing, 4 pending.Related: #1151 (same issue; this PR uses
obj.value[0].value.lengthinstead of addingcaptureAsn1).