CVE-2026-22698: Rustcrypto SM2 Elliptic Curve

High severity, CVSS 7.5. EPSS: 0.3% chance of exploitation in the next 30 days.

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.

Affected products

• Rustcrypto SM2 Elliptic Curve: version 0.14.0 only

Published 2026-01-10. Last modified 2026-06-17.