CVE-2021-34556: In the Linux kernel through 5.13.7, an unprivileged BPF program can obtain sensitive information from kerne...

Security readout for executives and security teams

CVE-2021-34556 is a Linux kernel information-disclosure issue. A local unprivileged user able to run BPF programs may infer sensitive kernel memory through a speculative execution side channel. This is mainly a concern on multi-user Linux systems, shared hosts, and container platforms that expose unprivileged BPF. Exposure is likely where Linux systems run kernels through 5.13.7 and allow unprivileged users or workloads to load BPF programs. Internet reachability alone is not the primary factor; local code execution capability matters. Treat as a targeted local information-disclosure risk, not an emergency remote takeover. Patch in normal kernel security cycles, with higher priority for shared Linux infrastructure and environments hosting untrusted workloads. Mitigation focus: Apply vendor Linux kernel security updates for affected distributions.; Upgrade to kernels containing the referenced upstream fixes.; Check Fedora and Debian advisories for fixed package versions..

Prepared

Jun 2, 2026, 19:01 UTC (UTC+00:00)

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.