open-quantum-safe liboqs up to 0.15.x FrodoKEM util.c ct_select information disclosure

Summaryinfo

A vulnerability classified as problematic has been found in open-quantum-safe liboqs up to 0.15.x. Impacted is the function ct_select of the file src/kem/frodokem/external/util.c of the component FrodoKEM. This manipulation causes information disclosure. This vulnerability is handled as CVE-2026-44519. It is possible to launch the attack on the local host. There is not any exploit available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability was found in open-quantum-safe liboqs up to 0.15.x. It has been declared as problematic. Affected by this vulnerability is the function ct_select of the file src/kem/frodokem/external/util.c of the component FrodoKEM. The manipulation with an unknown input leads to a information disclosure vulnerability. The CWE definition for the vulnerability is CWE-200. The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. As an impact it is known to affect confidentiality. The summary by CVE is:

liboqs is a C-language cryptographic library that provides implementations of post-quantum cryptography algorithms. Prior to 0.16.0, the ct_select function in src/kem/frodokem/external/util.c for the FrodoKEM-640, FrodoKEM-976, and FrodoKEM-1344 AES and SHAKE reference variants lacks a value barrier in the Fujisaki-Okamoto implicit-rejection path. When compiled with Clang 17 or later at an affected optimization level such as -Os, the compiler can emit a secret-dependent conditional load, causing the real and rejection secret paths to leave distinguishable cache residency after successful and failed decapsulation. A local attacker able to perform repeated cache-timing measurements may use this oracle as part of a private-key recovery attack. Default -O3 builds vectorize both source loads and do not exhibit the reported behavior, and the advisory does not report the same generated memory-access pattern in NTRU, NTRU-Prime, BIKE, HQC, Classic McEliece, Kyber, or the already-barriered ML-KEM implementation. This issue is fixed in version 0.16.0.

It is possible to read the advisory at github.com. This vulnerability is known as CVE-2026-44519 since 05/06/2026. The exploitation appears to be easy. Attacking locally is a requirement. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1592 according to MITRE ATT&CK.

Upgrading to version 0.16.0 eliminates this vulnerability.

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Productinfo

Vendor

• open-quantum-safe

Name

• liboqs

Version

• 0.1
• 0.2
• 0.3
• 0.4
• 0.5
• 0.6
• 0.7
• 0.8
• 0.9
• 0.10
• 0.11
• 0.12
• 0.13
• 0.14
• 0.15

Website

• Product: https://github.com/open-quantum-safe/liboqs/

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