CVE-2026-22698 — RustCrypto SM2-PKE has 32-bit Biased Nonce Vulnerability
RustCrypto: Elliptic Curves is general purpose Elliptic Curve Cryptography (ECC) support, including types and traits for representing various elliptic curve forms, scalars, poin…
Published: 2026-01-10 · CVSS: 8.7 · CVSS 4.0
RustCrypto: Elliptic Curves is general purpose Elliptic Curve Cryptography (ECC) support, including types and traits for representing various elliptic curve forms, scalars, points, and public/secret keys composed thereof. In versions 0.14.0-pre.0 and 0.14.0-rc.0, a critical vulnerability exists in the SM2 Public Key Encryption (PKE) implementation where the ephemeral nonce k is generated with severely reduced entropy. A unit mismatch error causes the nonce generation function to request only 32 bits of randomness instead of the expected 256 bits. This reduces the security of the encryption from a 128-bit level to a trivial 16-bit level, allowing a practical attack to recover the nonce k and decrypt any ciphertext given only the public key and ciphertext. This issue has been patched via commit e4f7778.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7