Medium severity · published Jul 28, 2026
CVE-2024-14041
ML-KEM (Kyber) decapsulation leaks private key information through non-constant-time division in message decoding and ciphertext compression (KyberSlash)
5.9
CVSS
0.5%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Confidentiality
High
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 40% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
BC
BC-JAVA · Legion of the Bouncy Castle Inc.
1.73 before 1.78 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2024-14041
CVE.org
https://www.cve.org/CVERecord?id=CVE-2024-14041
Patch
https://github.com/bcgit/bc-java/commit/1590247178f2280defa36421475f015175dfbe9e
Patch
https://github.com/bcgit/bc-java/commit/5adb2c5c5b462a332b01a012bea0784b40b904e5
Vendor Advisory
https://github.com/bcgit/bc-java/wiki/CVE-2024-14041
Exploit
https://kyberslash.cr.yp.to/
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