liboqs is a C-language cryptographic library that provides implementations of post-quantum cryptography algorithms. liboqs prior to version 0.13.0 supports the HQC algorithm, an algorithm with a theoretical design flaw which leads to large numbers of malformed ciphertexts sharing the same implicit rejection value. Currently, no concrete attack on the algorithm is known. However, prospective users of HQC must take extra care when using the algorithm in protocols involving key derivation. In particular, HQC does not provide the same security guarantees as Kyber or ML-KEM. There is currently no patch for the HQC flaw available in liboqs, so HQC is disabled by default in liboqs starting from version 0.13.0. OQS will update its implementation after the HQC team releases an updated algorithm specification.
History

Mon, 25 Aug 2025 14:15:00 +0000

Type Values Removed Values Added
First Time appeared Openquantumsafe
Openquantumsafe liboqs
CPEs cpe:2.3:a:openquantumsafe:liboqs:*:*:*:*:*:*:*:*
Vendors & Products Openquantumsafe
Openquantumsafe liboqs

Sat, 31 May 2025 03:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

threat_severity

Low


Fri, 30 May 2025 21:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Fri, 30 May 2025 19:30:00 +0000

Type Values Removed Values Added
Description liboqs is a C-language cryptographic library that provides implementations of post-quantum cryptography algorithms. liboqs prior to version 0.13.0 supports the HQC algorithm, an algorithm with a theoretical design flaw which leads to large numbers of malformed ciphertexts sharing the same implicit rejection value. Currently, no concrete attack on the algorithm is known. However, prospective users of HQC must take extra care when using the algorithm in protocols involving key derivation. In particular, HQC does not provide the same security guarantees as Kyber or ML-KEM. There is currently no patch for the HQC flaw available in liboqs, so HQC is disabled by default in liboqs starting from version 0.13.0. OQS will update its implementation after the HQC team releases an updated algorithm specification.
Title liboqs affected by theoretical design flaw in HQC
Weaknesses CWE-327
References
Metrics cvssV3_1

{'score': 3.7, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2025-05-30T20:43:37.178Z

Reserved: 2025-05-28T18:49:07.583Z

Link: CVE-2025-48946

cve-icon Vulnrichment

Updated: 2025-05-30T20:43:32.307Z

cve-icon NVD

Status : Analyzed

Published: 2025-05-30T20:15:43.710

Modified: 2025-08-25T14:06:29.650

Link: CVE-2025-48946

cve-icon Redhat

Severity : Low

Publid Date: 2025-05-30T19:21:14Z

Links: CVE-2025-48946 - Bugzilla