CVE-2025-48946 liboqs affected by theoretical design flaw in HQC

Low 3.7 Published 30 May 2025 Updated 30 May 2025

The HQC algorithm in liboqs has a theoretical design flaw affecting key derivation security, mitigated by disabling it by default in newer versions.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2025-48946?

CVE-2025-48946 is a low-severity vulnerability in open-quantum-safe liboqs, published on 30 May 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official 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.

Weakness: CWE-327

Which versions are affected by CVE-2025-48946?

It affects 1 product.

Products include Openquantumsafe Liboqs.

How do I fix CVE-2025-48946?

No fix has been published for CVE-2025-48946 yet. Limit exposure of the affected software until one is available.

Is CVE-2025-48946 being exploited?

There is no known exploitation of CVE-2025-48946 in the wild and no public exploit code.

Sources

Also known as GHSA-3rxw-4v8q-9gq5.