TI-2025-31084 Aliases CVE-2025-48946

liboqs affected by theoretical design flaw in HQC

LOW 17CWE-327Published 2025-05-30 · Updated 2025-05-30

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: High
Impact type: Information disclosure
Confidentiality · integrity · availability: Low · None · None
Fix status: Partial Red Hat: 1 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-327.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00248 16th percentileScored 2026-11-07

Fix Partial liboqs (open-quantum-safe): 0.13.0Red Hat: 1 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
open-quantum-safe	liboqs	before 0.13.0	0.13.0	Patch available	CNA

liboqs Vendoropen-quantum-safe Affected before 0.13.0 Fixed in 0.13.0 Patch available CNA

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:openquantumsafe:liboqs::::::::	before 0.13.0	Vulnerable	open-quantum-safe

cpe:2.3:a:openquantumsafe:liboqs:*:*:*:*:*:*:*:* Versions before 0.13.0 Vulnerable ·open-quantum-safe

Remediation

Fix · CNA liboqs (open-quantum-safe) Fixed in 0.13.0

Vendor assessments

Red Hat

Red Hat rating: Low. Red Hat's page for this CVE →

Product	Status	Plan or fix
Red Hat Enterprise Linux 10	Affected	No fix yet: Fix deferred

Timeline

2026-10-02 Threatist record created from CVE-2025-48946

References

Patch 1

https://github.com/open-quantum-safe/liboqs/commit/a7d698ca9c9d98990647459253183cbe29c550af

Advisory 1

https://github.com/open-quantum-safe/liboqs/security/advisories/GHSA-3rxw-4v8q-9gq5

Other 2

TI-2024-20867 An issue in Open Quantum Safe liboqs v.10.0 allows a remote attacker to escalate… CVSS 3.1CRITICAL 9.8
TI-2024-36253 liboqs has a correctness error in HQC decapsulation CVSS 3.1HIGH 7.5
TI-2024-24191 Control-flow timing leak in Kyber reference implementation when compiled with Clang 15-18 for -Os, -O1 and other options CVSS 3.1HIGH 7.5
TI-2026-34064 liboqs: Heap-buffer-overflow in XMSS verification path via OID-controlled parameter mismatch (xmss_commons.c:194) CVSS 3.1MEDIUM 5.3
TI-2026-32448 liboqs: XMSS Buffer Overread Bug CVSS 3.1MEDIUM 5.3
TI-2025-32600 liboqs secret-dependent branching in HQC reference implementation when compiled with Clang 17-20 CVSS 3.1MEDIUM 5.9

Sources

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