PT-2026-30292 · Npm · Fido2-Lib
Published
2026-03-24
·
Updated
2026-03-24
CVSS v3.1
7.5
High
| Vector | AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
Summary
fido2-lib v3.x depends on cbor-x (~1.6.0), which optionally pulls in cbor-extract (C++ native addon). cbor-extract <= 2.2.0 has a heap buffer over-read in
extractStrings() — a 5-byte CBOR payload crashes Node.js with SIGSEGV. No JS exception, no try/catch, process dead.The crash triggers during WebAuthn registration when the server decodes the attestation object. An attacker sends a crafted authenticator response to the registration endpoint — single request, unauthenticated, instant kill.
Fixed in cbor-extract@2.2.1 / cbor-x@1.6.3 (2026-03-08). fido2-lib@3.5.7 still pins cbor-x ~1.6.0 which resolves to vulnerable cbor-extract.
Affected versions
fido2-lib <= 3.5.7 (introduced cbor-x dependency). fido2-lib 2.x uses the old
cbor package — not affected.Only affects systems where
cbor-extract native addon is installed (prebuilt binary available for platform). Pure JS fallback is safe.PoC
js
const { decode } = require("cbor-x");
decode(Buffer.from("7a10000000", "hex")); // exit code 139 (SIGSEGV)CBOR text string header claiming 268MB in a 5-byte buffer.
extractStrings() in extract.cpp line 87 calls readString() without bounds check. Reads past buffer into unmapped memory.In context: attacker intercepts WebAuthn registration response, replaces
attestationObject with the 5-byte payload, POSTs to the registration verification endpoint. Server calls attestationResult() → cbor-x.decode() → cbor-extract → SIGSEGV.Fix
Bump cbor-x to >= 1.6.3 (which pulls cbor-extract >= 2.2.1).
diff
-"cbor-x": "~1.6.0"
+"cbor-x": "^1.6.3"— Malik X (@Xvush)
Fix
Out of bounds Read
Buffer Over-read
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Related Identifiers
Affected Products
Fido2-Lib