GHSA-4642-5mcj-2rqw

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GHSA-4642-5mcj-2rqw

Summary: Forge: ASN.1 OID first arc truncation in asn1.oidToDer

Details: ### Summary `asn1.oidToDer()` did not range-check the first two arcs of an OID string, so an OID such as `0.42.840.113549.1.1.1` or `4294977127.18.840.113549.1.1.1` was encoded as the DER of a different OID (here rsaEncryption, `1.2.840.113549.1.1.1`). This is an incomplete fix of CVE-2025-66030. Fixed in node-forge 1.4.1. ### Details X.690 section 8.19 encodes the first two arcs of an OID as one subidentifier, `40 * arc1 + arc2`, where the first arc is 0, 1 or 2 and the second arc is at most 39 when the first is 0 or 1. `asn1.oidToDer()` in `lib/asn1.js` computed that value with no range check and wrote it with `putByte()`, which keeps only the low 16 bits. Out-of-range first arcs therefore produced the encoding of a different OID: `0.42.840.113549.1.1.1` gives `40 * 0 + 42 = 42` and `4294977127.18.840.113549.1.1.1` wraps to 42, both the first byte of rsaEncryption. The fix for CVE-2025-66030 (GHSA-65ch-62r8-g69g, node-forge 1.3.2) added a 32-bit check for the later arcs only. A related encoding bug made valid OIDs with a first subidentifier above 127 (`2.48` and higher, e.g. `2.999`) encode and decode incorrectly, because the first subidentifier was always written and read as a single byte. The fix rejects out-of-range first arcs and encodes and decodes the first subidentifier in base 128 like the others (the latter from public PR #1148). ### Patches Fixed in node-forge 1.4.1. `asn1.oidToDer()` throws for OIDs with out-of-range first arcs, and the first subidentifier is encoded and decoded correctly. ### Workarounds Validate OID strings from untrusted input before passing them to node-forge: the first arc must be 0, 1 or 2, and the second arc at most 39 when the first arc is 0 or 1. ### Credits Reported by wzc. The first subidentifier encoding fix is from PR #1148 by @spokodev. ### Proof of concept var forge = require('node-forge'); var der = forge.asn1.oidToDer('0.42.840.113549.1.1.1'); console.log(der.toHex()); // 2a864886f70d010101 console.log(forge.asn1.derToOid(der)); // 1.2.840.113549.1.1.1 On 1.4.0 the out-of-range OID string encodes to exactly the DER of rsaEncryption (the same happens with `4294977127.18.840.113549.1.1.1`). On 1.4.1 `oidToDer()` throws "Invalid OID; the first two arcs are out of range.". Regression tests are in tests/unit/asn1.js ("should reject OIDs with out of range first arcs"). ### Impact Applications that accept OID strings from untrusted input, check or authorize them as strings, and then encode them with node-forge (for example when building certificates, CSRs or other ASN.1 structures from user-supplied extension or attribute OIDs) can be made to emit a different, trusted OID than the one that was checked. Parsing DER is not affected. There is no confidentiality or availability impact.

References: https://github.com/digitalbazaar/forge/security/advisories/GHSA-4642-5mcj-2rqw, https://nvd.nist.gov/vuln/detail/CVE-2026-118775, https://github.com/digitalbazaar/forge/commit/e56a3dde8e4e63bae566bb32546eeaf92f515e1e, https://github.com/digitalbazaar/forge, https://github.com/digitalbazaar/forge/releases/tag/v1.4.1