---
id: "CVE-2026-98655"
kind: "vulnerability"
aliases: ["CVE-2026-98655"]
title: "Linux kernel: unprivileged perf text-poke events leak kernel text addresses"
severity: "low"
cvss: null
epss: null
exploited: false
status: "open"
category: "infrastructure"
products: []
ecosystems: []
tags: ["infrastructure", "kernel", "linux", "multi-user-hosts"]
not_affected_if: ["single-user-host"]
published_at: "2026-10-18T16:17:18+00:00"
first_seen_at: "2026-10-23T21:57:16+00:00"
updated_at: "2026-10-25T05:19:36+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98655", "first_seen_at": "2026-10-23T21:57:16+00:00"}]
---

# Linux kernel: unprivileged perf text-poke events leak kernel text addresses

Linux perf text-poke sideband records were readable without kernel perf access, even with exclude_kernel set. An unprivileged local user can observe relocated kernel instruction addresses, which reveals the kernel text base despite KASLR.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- unknown

## Fix

- Update to a Linux kernel release that includes the fix 'perf: Require kernel access for text poke events' (exact version unknown from sources)

## Timeline

- 2026-10-23T21:57:16+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-98655

## From the sources

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.

---

_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_