# CVE-2024-35895: bpf, sockmap: Prevent lock inversion deadlock in map delete elem

> A local attacker can trigger a kernel deadlock via BPF tracing programs, causing a denial of service.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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:** 15 Oct 2026
- **Also known as:** BELL-CVE-2024-35895, DEBIAN-CVE-2024-35895, GHSA-37c3-qm4g-jf9g, ROOT-OS-UBUNTU-2404-CVE-2024-35895, UBUNTU-CVE-2024-35895

## What is CVE-2024-35895?

CVE-2024-35895 is a medium-severity vulnerability in Debian Debian Linux, 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, sockmap: Prevent lock inversion deadlock in map delete elem

syzkaller started using corpuses where a BPF tracing program deletes
elements from a sockmap/sockhash map. Because BPF tracing programs can be
invoked from any interrupt context, locks taken during a map_delete_elem
operation must be hardirq-safe. Otherwise a deadlock due to lock inversion
is possible, as reported by lockdep:

       CPU0                    CPU1
       ----                    ----
  lock(&htab->buckets[i].lock);
                               local_irq_disable();
                               lock(&host->lock);
                               lock(&htab->buckets[i].lock);
  <Interrupt>
    lock(&host->lock);

Locks in sockmap are hardirq-unsafe by design. We expects elements to be
deleted from sockmap/sockhash only in task (normal) context with interrupts
enabled, or in softirq context.

Detect when map_delete_elem operation is invoked from a context which is
_not_ hardirq-unsafe, that is interrupts are disabled, and bail out with an
error.

Note that map updates are not affected by this issue. BPF verifier does not
allow updating sockmap/sockhash from a BPF tracing program today.

Weakness: CWE-667 (Improper Locking)

## Which versions are affected by CVE-2024-35895?

It affects 2 products.


Products: Debian Debian Linux, Linux kernel.

## How do I fix CVE-2024-35895?

Apply the vendor's patch.

## Is CVE-2024-35895 being exploited?

There is no known exploitation of CVE-2024-35895 in the wild and no public exploit code.

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- [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild)
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- [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-35895 and fix it if it is affected.

What it is: CVE-2024-35895 is a medium-severity vulnerability in Debian Debian Linux, 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-2024-35895 in the wild and no public exploit code.

Affected product: Debian Debian 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-2024-35895/ (Markdown: https://insights.sbomify.com/CVE-2024-35895/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-35895
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-35895
- OSV: https://osv.dev/vulnerability/CVE-2024-35895

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-35895/
Summaries are generated and may contain mistakes; the official description above is the record.