Vulnerability details

CVE-2026-22698

RustCrypto elliptic-curves

RustCrypto SM2-PKE has 32-bit Biased Nonce Vulnerability

CVSS 4.0
8.7High

Official description

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.

CVSS scores

ScoreVersionSourceVector
8.7High 4.0 CVEProject cvelistV5 (CNA) (GitHub_M) CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

Affected products

VendorProductVersionsSource
RustCrypto elliptic-curves = 0.14.0-pre.0 CVEProject cvelistV5 (CNA)
RustCrypto elliptic-curves = 0.14.0-rc.0 CVEProject cvelistV5 (CNA)

References and advisories

6
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Details

Published
2026-01-10
Last updated
2026-01-12
State
Published
Assigner (CNA)
GitHub_M

Exploit prediction (EPSS)

0.27%
Probability of exploitation in 30 days
19.8%
Percentile (among all CVEs)

SSVC assessment (CISA)

Automatable
Yes
Exploitation
None
Technical impact
Partial

Weaknesses (CWE)

  • CWE-331
    Insufficient Entropy