CVE-2023-52920 Linux CVE debrief

Who should care

Linux kernel maintainers, distro security teams, and operators running eBPF/BPF workloads on kernels older than 6.8 should review this CVE, especially where verifier behavior matters for networking, tracing, or other BPF-heavy deployments.

Technical summary

The kernel fix changes how the BPF verifier records instruction history for register spill/fill operations to and from the stack. It extends history tracking so spills and fills are tracked even when they occur through registers other than r10 after copying and adjusting the frame pointer, and it adds per-instruction flags for stack slot index and frame number. The change also resets and reuses the current history-entry pointer to avoid ambiguous backtracking state. In the supplied NVD metadata, the issue is classified as CWE-476 and scored CVSS v3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.

Defensive priority

Medium

Recommended defensive actions

• Upgrade Linux kernels to a release that includes the fix; NVD marks versions before 6.8 as vulnerable.
• Check vendor backports and distro kernel advisories, since fixed kernels may retain older version numbers.
• Prioritize systems that run untrusted or frequently changing BPF programs, or that rely heavily on verifier-sensitive workflows.
• Validate exposure by confirming whether the relevant kernel build includes the official fix references in its changelog or backport set.

Evidence notes

This debrief is based on the supplied NVD record and the kernel references it cites. The CVE was first published on 2024-11-05T10:15:24.580Z and later modified on 2026-05-17T16:16:13.030Z. NVD lists Linux kernel versions before 6.8 as vulnerable, assigns CVSS v3.1 5.5 MEDIUM, and maps the issue to CWE-476. The supplied kernel description frames the issue as a BPF verifier precision-tracking fix rather than a standalone exploit narrative, so downstream vendor backports should be checked for real-world exposure.

Official resources