liboqs: XMSS Buffer Overread Bug
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- None · None · Low
- Fix status
- Partial Red Hat: 1 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- 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 0.16.0 | 0.16.0 | Patch available | CNA |
- liboqs Vendoropen-quantum-safe Affected before 0.16.0 Fixed in 0.16.0 Patch available CNA
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:openquantumsafe:liboqs:*:*:*:*:*:*:*:* | up to 0.15.0 | Vulnerable | open-quantum-safe |
- cpe:2.3:a:openquantumsafe:liboqs:*:*:*:*:*:*:*:* Versions up to 0.15.0 Vulnerable ·open-quantum-safe
Remediation
- Fix · CNA liboqs (open-quantum-safe) Fixed in 0.16.0
Vendor assessments
Red Hat
Red Hat rating: Moderate. 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-2026-44518
References
More open-quantum-safe Liboqs vulnerabilities
- 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-2025-32600 liboqs secret-dependent branching in HQC reference implementation when compiled with Clang 17-20 CVSS 3.1MEDIUM 5.9
- TI-2025-31084 liboqs affected by theoretical design flaw in HQC CVSS 3.1LOW 3.7
Sources
- CVE-2026-44518 · CVE Program
- CVE-2026-44518 · NVD
- FIRST EPSS
- CVE-2026-44518 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences