An uninitialized function‑pointer dereference in OQS_KEM_encaps_derand can crash the calling process when an application invokes this routine on any of the six NTRU KEM schemes that do not support derandomized encapsulation. The flaw arises because the encaps_derand member is omitted from the scheme constructors and the library allocates the OQS_KEM objects without zero‑initialization, so a residual heap value is used. The result is a denial of service for the process that holds the library instance. The identified weakness corresponds to CWE‑824.

The vulnerability affects the open‑quantum‑safe liboqs cryptographic library version 0.15.x and earlier. Any application that links liboqs and instantiates one of the following NTRU KEMs – NTRU‑HPS‑2048‑509, NTRU‑HPS‑2048‑677, NTRU‑HPS‑4096‑821, NTRU‑HPS‑4096‑1229, NTRU‑HRSS‑701, or NTRU‑HRSS‑1373 – is susceptible. The flaw is fixed in liboqs release 0.16.0. This inference is based on the fact that version 0.16.0 is the first release that fixes the issue, implying that prior releases such as 0.15.x are vulnerable.

The CVSS score of 5.3 indicates a moderate severity, and the lack of an EPSS score suggests that the exploitation probability has not been measured. The vulnerability is not listed in the CISA KEV catalog. The most likely attack vector is local or co‑resident, requiring the application to call the vulnerable function; remote exploitation would require additional vulnerabilities. The impact is a process crash leading to service disruption.