Skip to main content
← All vulnerabilities
CVE-2024-14041

ML-KEM (Kyber) decapsulation leaks private key information through non-constant-time division in message decoding and ciphertext compression (KyberSlash)

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 1.78
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: no
  • Technical impact: partial

Summary

In Bouncy Castle for Java from 1.73 to before 1.78, three ML-KEM (CRYSTALS-Kyber) routines divided secret-derived polynomial coefficients by the modulus q: Poly.toMsg, which decodes the decrypted message, and the ciphertext compression routines Poly.compressPoly and PolyVec.compressPolyVec. An attacker able to measure the timing of a large number of decapsulations performed with the same long-term private key can recover that key. These are the KyberSlash1 (Poly.toMsg) and KyberSlash2 (ciphertext compression) divisions. Compression performed during encapsulation operates on values that become the public ciphertext and is not affected.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: no · Technical impact: partial

  3. Record last updated

Affected versions

  • bcprov

    From 1.73 · fixed in 1.78

References 4

GitHub · bcgit/bc-java

kyberslash.cr.yp.to