# CVE-2026-74344: bpf: Clear rb node linkage when freeing bpf_rb_root

> A use-after-free in the Linux kernel BPF subsystem allows attackers to corrupt memory and potentially execute arbitrary code or escalate privileges.

- **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:** 15 Aug 2026
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-96288, BELL-CVE-2026-74344, DEBIAN-CVE-2026-74344, GHSA-345m-8q8p-cx77, UBUNTU-CVE-2026-74344

## What is CVE-2026-74344?

CVE-2026-74344 is a high-severity use after free vulnerability in Linux, published on 15 Aug 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:

bpf: Clear rb node linkage when freeing bpf_rb_root

bpf_rb_root_free() detaches the root by copying the current rb_root_cached
and then replacing the live root with RB_ROOT_CACHED. It then walks the
copied root and drops each object contained in the tree.

This leaves the rb node state intact while dropping the object. If the
object is refcounted and survives the drop, its bpf_rb_node_kern still
contains an owner pointer to the freed root and stale rb tree linkage. If
a later bpf_rb_root allocation reuses the same address, bpf_rbtree_remove()
can incorrectly pass the owner check and call rb_erase_cached() on a node
whose rb pointers belong to the old tree.

Mirror the list draining behavior by marking nodes as busy while the root
is being detached, then clear the rb node and release the owner before
dropping the containing object. This makes surviving nodes unowned and
safe to reject from remove or accept for a later add.

## Which versions are affected by CVE-2026-74344?


## How do I fix CVE-2026-74344?

Apply the vendor's patch.

## Is CVE-2026-74344 being exploited?

There is no known exploitation of CVE-2026-74344 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-74344 and fix it if it is affected.

What it is: CVE-2026-74344 is a high-severity use after free vulnerability in Linux, published on 15 Aug 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-2026-74344 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-2026-74344/ (Markdown: https://insights.sbomify.com/CVE-2026-74344/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-74344
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-74344
- OSV: https://osv.dev/vulnerability/CVE-2026-74344

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-74344/
Summaries are generated and may contain mistakes; the official description above is the record.