Vulnerability Details CVE-2026-22698
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.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.0
EPSS Ranking 12.3%
CVSS Severity
CVSS v3 Score 7.5
References
- https://crates.io/crates/sm2/0.14.0-pre.0
- https://crates.io/crates/sm2/0.14.0-rc.0
- https://github.com/RustCrypto/elliptic-curves/commit/4781762f23ff22ab34763410f648128055c93731
- https://github.com/RustCrypto/elliptic-curves/commit/e4f77788130d065d760e57fb109370827110a525
- https://github.com/RustCrypto/elliptic-curves/pull/1600
- https://github.com/RustCrypto/elliptic-curves/security/advisories/GHSA-w3g8-fp6j-wvqw
Products affected by CVE-2026-22698
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cpe:2.3:a:rustcrypto:sm2_elliptic_curve:0.14.0