Copy Fail (CVE-2026-31431): 9-year-old Linux kernel LPE found by Theori's Xint Code

What it is

"Copy Fail" (CVE-2026-31431) is a Linux kernel local privilege escalation vulnerability documented by Theori's Xint Code team. The fetched page itself is only the "Tested Distro / Version" table — it does not describe the bug's mechanism — but it pins the exact confirmed-vulnerable kernel builds, which the summary gives for only one distro.

Preconditions / Affected

The writeup confirms exploitation on these specific kernel builds:

As a local privilege escalation, it requires an existing unprivileged foothold on the host; there is no network-facing vector in the tested cases.

Caveats

The page content available here is limited to the tested-versions table — it does not state the underlying mechanism, an exploitation procedure, patch identifiers, or detection guidance. The four builds above are confirmed-vulnerable data points, not a full affected-version range; kernels between these builds and any fixed release are not characterized on this page. Consult the linked GitHub writeup directly for the exploit technique and any remediation.