CVE-2025-48946

liboqs affected by theoretical design flaw in HQC

Published May 30, 2025 CVSS 3.1 · 3.7 Low EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
EUVD EUVD EUVD-2025-16528 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
Type Values Removed Values Added
First Time appeared Openquantumsafe
Openquantumsafe liboqs
CPEs cpe:2.3:a:openquantumsafe:liboqs:*:*:*:*:*:*:*:*
Vendors & Products Openquantumsafe
Openquantumsafe liboqs
Type Values Removed Values Added
Metrics ssvc

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

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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
May 30, 2025, 8:43 PM
Reserved
May 28, 2025, 6:49 PM
Status
Analyzed
Published
May 30, 2025, 8:15 PM
Modified
Jun 17, 2026, 9:30 AM
Severity
Low
Public date
May 30, 2025, 7:21 PM