CVE-2026-58089 hwpmc fails to detach PMCs during exec credential transitions

FreeBSD 's hwpmc(4) driver (hardware performance monitoring counters) contains an inverted check that fails to detach PMCs owned by unprivileged processes during execve(2) credential transitions to setuid or setgid binaries. An unprivileged local user who has attached PMCs to a target process can...

PT-2026-81927

When a process calls execve2 to execute a setuid or setgid image, hwpmc4 is supposed to detach PMCs owned by unprivileged processes. An inverted check meant that this scenario was not handled properly. An unprivileged local user who has attached PMCs to a process can continue monitoring it after...

FreeBSD -- hwpmc fails to detach PMCs during exec credential transitions

Problem Description: When a process calls execve2 to execute a setuid or setgid image, hwpmc4 is supposed to detach PMCs owned by unprivileged processes. An inverted check meant that this scenario was not handled properly. Impact: An unprivileged local user who has attached PMCs to a process can...