Out-of-bounds Read in Open-Quantum-Safe Liboqs
CVE-2026-44518
liboqs is a C-language cryptographic library that provides implementations of post-quantum cryptography algorithms. Prior to 0.16.0, an out-of-bounds read has been identified in the XMSS and XMSS^MT stateful signature verification code. When the verification function is called with a signature buffer shorter than the expected signature size for the given parameter set, the implementation does not validate the caller-supplied length and proceeds to read past the end of the buffer. The out-of-bounds bytes are consumed only as input to an internal hash computation and are not returned to the caller, so no oracle exists to leak their contents to an attacker. The primary observable effect is a possible crash (denial of service) of the verifying process if the read crosses into an unmapped memory page. This vulnerability is fixed in 0.16.0.
Vulnerability class: Drupalgeddon 2 (CVE-2018-7600)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.
EPSS exploit prediction
EPSS: 0.003 (21.8th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 22nd percentile — 21.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000
Affected products
- Open-Quantum-Safe Liboqs — versions < 0.16.0
- Openquantumsafe Liboqs
Weakness classification (CWE)
References
Frequently asked questions
- What is CVE-2026-44518?
- CVE-2026-44518 is a medium-severity vulnerability in Open-Quantum-Safe Liboqs, classified under Improper Input Validation. CVSS score: 5.3/10. Published 2026-05-29.
- How severe is CVE-2026-44518?
- Medium severity. CVSS v3 base score is 5.3 out of 10.