# CVE-2026-89988: kprobes: Protect kprobe_blacklist with RCU

> A use-after-free vulnerability in the Linux kernel's kprobes subsystem allows attackers to cause denial of service or execute arbitrary code via concurrent module unloading.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **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:** Yes
- **Published:** 16 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-101195, BELL-CVE-2026-89988, DEBIAN-CVE-2026-89988, GHSA-8536-v82h-gp8m, UBUNTU-CVE-2026-89988

## What is CVE-2026-89988?

CVE-2026-89988 is a high-severity use after free vulnerability in Linux, published on 16 Sep 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:

kprobes: Protect kprobe_blacklist with RCU

__within_kprobe_blacklist() traverses kprobe_blacklist without holding
kprobe_mutex. When a module is unloaded, kprobe_remove_area_blacklist()
removes blacklist entries and immediately frees them with kfree().
A concurrent call to within_kprobe_blacklist() can therefore dereference
freed memory.

Furthermore, within_kprobe_blacklist() can be called in atomic or
non-preemptible contexts where the sleeping kprobe_mutex cannot be taken.

Protect kprobe_blacklist with RCU. Use guard(rcu)() and
list_for_each_entry_rcu() for traversal, list_add_tail_rcu() for
insertions, list_del_rcu() for deletions, and kfree_rcu() to reclaim
entries safely after a grace period.

## Which versions are affected by CVE-2026-89988?


## How do I fix CVE-2026-89988?

Apply the vendor's patch.

## Is CVE-2026-89988 being exploited?

There is no known exploitation of CVE-2026-89988 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-89988 and fix it if it is affected.

What it is: CVE-2026-89988 is a high-severity use after free vulnerability in Linux, published on 16 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-89988 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-89988/ (Markdown: https://insights.sbomify.com/CVE-2026-89988/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-89988
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-89988
- OSV: https://osv.dev/vulnerability/CVE-2026-89988

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-89988/
Summaries are generated and may contain mistakes; the official description above is the record.