CVE-2026-98655 perf: Require kernel access for text poke events
Unprivileged local users can bypass KASLR by reading kernel text poke events, revealing runtime kernel addresses.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-98655?
CVE-2026-98655 is a vulnerability in Linux, published on 18 Oct 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official 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.
Which versions are affected by CVE-2026-98655?
How do I fix CVE-2026-98655?
Apply the vendor's patch.
Is CVE-2026-98655 being exploited?
There is no known exploitation of CVE-2026-98655 in the wild and no public exploit code.
Sources
Also known as AZL-109188, BELL-CVE-2026-98655, DEBIAN-CVE-2026-98655, GHSA-73f2-5qh8-h6cg, UBUNTU-CVE-2026-98655.