The vulnerability arises when the GNU C Library’s nscd client calls the memcmp function with inputs that may be modified concurrently by other threads. In glibc 2.36 and the backported 2.35 branch, an optimized memcmp on x86_64 can crash under these undefined conditions. This leads to a crash of the nscd client and any application that uses it, causing a denial‑of‑service. The weakness is classed as CWE‑366 (Concurrent Modification of Data).

The issue affects the GNU C Library (glibc) on 64‑bit x86 systems. Versions 2.36 and the 2.35 branch, as well as any releases where the SSE2 memcmp optimization was backported, are vulnerable. Distributions that cherry‑picked this optimization should also be considered at risk.

The CVSS score of 6.2 indicates moderate severity, while the EPSS score of less than 1 % suggests a low likelihood of exploitation, and the flaw is not listed in CISA’s KEV catalog. The most probable attack vector is local or within the same host; an attacker can induce the crash by generating high load on nscd or by calling NSS‑backed functions that rely on the nscd client. Exploitation results in a crash that can be leveraged for denial of service, but it does not expose data or allow code execution.