CVE-2026-98655

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

perf: Require kernel access for text poke events

Perf events with exclude_kernel=1 can be opened without kernel perf

access. However, exclude_kernel does not suppress text-poke sideband

records. Every PERF_RECORD_TEXT_POKE is marked PERF_RECORD_MISC_KERNEL

and contains a raw kernel instruction address.

An unprivileged task can therefore open and mmap a task-local software

event with text_poke=1. Both opening a count-only tracepoint event and

configuring UDP GRO for ESP-in-UDP cause updates to inline static calls;

the observer receives the relocated addresses of the modified instructions.

For a known kernel image, any such address reveals the runtime kernel

text base despite KASLR.

Call perf_allow_kernel() whenever attr.text_poke is set, regardless of

exclude_kernel. Events that neither monitor kernel execution nor request

text-poke records retain their existing permissions.

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References