# CVE-2025-38502: bpf: Fix oob access in cgroup local storage

> An out-of-bounds access in Linux kernel cgroup local storage via tail calls allows attackers to potentially execute 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:** 16 Aug 2025
- **Updated:** 15 Oct 2026
- **Also known as:** AZL-66359, AZL-73473, BELL-CVE-2025-38502, DEBIAN-CVE-2025-38502, GHSA-x96j-4m6x-jcvx, ROOT-OS-DEBIAN-11-CVE-2025-38502, ROOT-OS-DEBIAN-12-CVE-2025-38502, ROOT-OS-DEBIAN-13-CVE-2025-38502, ROOT-OS-UBUNTU-2204-CVE-2025-38502, ROOT-OS-UBUNTU-2404-CVE-2025-38502, UBUNTU-CVE-2025-38502

## What is CVE-2025-38502?

CVE-2025-38502 is a high-severity memory corruption vulnerability in Debian Debian Linux, published on 16 Aug 2025. 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: Fix oob access in cgroup local storage

Lonial reported that an out-of-bounds access in cgroup local storage
can be crafted via tail calls. Given two programs each utilizing a
cgroup local storage with a different value size, and one program
doing a tail call into the other. The verifier will validate each of
the indivial programs just fine. However, in the runtime context
the bpf_cg_run_ctx holds an bpf_prog_array_item which contains the
BPF program as well as any cgroup local storage flavor the program
uses. Helpers such as bpf_get_local_storage() pick this up from the
runtime context:

  ctx = container_of(current->bpf_ctx, struct bpf_cg_run_ctx, run_ctx);
  storage = ctx->prog_item->cgroup_storage[stype];

  if (stype == BPF_CGROUP_STORAGE_SHARED)
    ptr = &READ_ONCE(storage->buf)->data[0];
  else
    ptr = this_cpu_ptr(storage->percpu_buf);

For the second program which was called from the originally attached
one, this means bpf_get_local_storage() will pick up the former
program's map, not its own. With mismatching sizes, this can result
in an unintended out-of-bounds access.

To fix this issue, we need to extend bpf_map_owner with an array of
storage_cookie[] to match on i) the exact maps from the original
program if the second program was using bpf_get_local_storage(), or
ii) allow the tail call combination if the second program was not
using any of the cgroup local storage maps.

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2025-38502?

It affects 3 products.


Products: Debian Debian Linux, Linux kernel, Siemens Simatic Cn 4100 Firmware.

## How do I fix CVE-2025-38502?

Apply the vendor's patch.

## Is CVE-2025-38502 being exploited?

There is no known exploitation of CVE-2025-38502 in the wild and no public exploit code.

Public exploit code:

- CVE-2025-38502 Linux LPE. BPF cgroup local storage OOB via tail calls. Affected kernels: 5.9–5.15.191, 5.16–6.1.150, 6.2–6.6.104, 6.7–6.12.45, 6.13–6.16.0; fixed in 5.15.192, 6.1.151, 6.6.105, 6.12.46, 6.16.1, 6.17-rc1 (github_poc): https://github.com/abraxas/CVE-2025-38502-Linux-LPE

## Other vulnerabilities in Debian Debian Linux

- [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild)
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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)
- [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild)
- [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-2025-38502 and fix it if it is affected.

What it is: CVE-2025-38502 is a high-severity memory corruption vulnerability in Debian Debian Linux, published on 16 Aug 2025. 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-2025-38502 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-2025-38502/ (Markdown: https://insights.sbomify.com/CVE-2025-38502/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-38502
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-38502
- OSV: https://osv.dev/vulnerability/CVE-2025-38502

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-38502/
Summaries are generated and may contain mistakes; the official description above is the record.