Bug 2483392 (CVE-2026-44518)

Summary: CVE-2026-44518 liboqs: liboqs: Denial of Service due to out-of-bounds read in XMSS/XMSS^MT signature verification
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in liboqs, a C-language cryptographic library. An out-of-bounds read vulnerability exists in the XMSS and XMSS^MT stateful signature verification code. A remote attacker could exploit this by providing a malformed signature that is shorter than expected. This could lead to a denial of service (DoS) if the verifying process attempts to read beyond allocated memory, potentially causing a crash.
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Description OSIDB Bzimport 2026-05-29 19:01:54 UTC 
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.