# CVE-2024-35860: bpf: support deferring bpf_link dealloc to after RCU grace period

> A use-after-free vulnerability in the Linux kernel BPF subsystem allows attackers to execute arbitrary code or escalate privileges via race conditions during link deallocation.

- **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:** 19 May 2024
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2024-35860, DEBIAN-CVE-2024-35860, GHSA-3v8r-vqv8-3pmc, ROOT-OS-DEBIAN-12-CVE-2024-35860, UBUNTU-CVE-2024-35860

## What is CVE-2024-35860?

CVE-2024-35860 is a high-severity use after free vulnerability in Linux kernel, published on 19 May 2024. 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: support deferring bpf_link dealloc to after RCU grace period

BPF link for some program types is passed as a "context" which can be
used by those BPF programs to look up additional information. E.g., for
multi-kprobes and multi-uprobes, link is used to fetch BPF cookie values.

Because of this runtime dependency, when bpf_link refcnt drops to zero
there could still be active BPF programs running accessing link data.

This patch adds generic support to defer bpf_link dealloc callback to
after RCU GP, if requested. This is done by exposing two different
deallocation callbacks, one synchronous and one deferred. If deferred
one is provided, bpf_link_free() will schedule dealloc_deferred()
callback to happen after RCU GP.

BPF is using two flavors of RCU: "classic" non-sleepable one and RCU
tasks trace one. The latter is used when sleepable BPF programs are
used. bpf_link_free() accommodates that by checking underlying BPF
program's sleepable flag, and goes either through normal RCU GP only for
non-sleepable, or through RCU tasks trace GP *and* then normal RCU GP
(taking into account rcu_trace_implies_rcu_gp() optimization), if BPF
program is sleepable.

We use this for multi-kprobe and multi-uprobe links, which dereference
link during program run. We also preventively switch raw_tp link to use
deferred dealloc callback, as upcoming changes in bpf-next tree expose
raw_tp link data (specifically, cookie value) to BPF program at runtime
as well.

## Which versions are affected by CVE-2024-35860?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2024-35860?

Apply the vendor's patch.

## Is CVE-2024-35860 being exploited?

There is no known exploitation of CVE-2024-35860 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-35860 and fix it if it is affected.

What it is: CVE-2024-35860 is a high-severity use after free vulnerability in Linux kernel, published on 19 May 2024. 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-2024-35860 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2024-35860/ (Markdown: https://insights.sbomify.com/CVE-2024-35860/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-35860
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-35860
- OSV: https://osv.dev/vulnerability/CVE-2024-35860

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-35860/
Summaries are generated and may contain mistakes; the official description above is the record.