# CVE-2025-38233: powerpc64/ftrace: fix clobbered r15 during livepatching

> A kernel bug in powerpc64 ftrace livepatching fails to restore register r15, causing memory corruption and system crashes.

- **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:** 4 Jul 2025
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2025-38233, GHSA-mfmj-296r-5fqr, UBUNTU-CVE-2025-38233

## What is CVE-2025-38233?

CVE-2025-38233 is a high-severity memory corruption vulnerability in Linux kernel, published on 4 Jul 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:

powerpc64/ftrace: fix clobbered r15 during livepatching

While r15 is clobbered always with PPC_FTRACE_OUT_OF_LINE, it is
not restored in livepatch sequence leading to not so obvious fails
like below:

  BUG: Unable to handle kernel data access on write at 0xc0000000000f9078
  Faulting instruction address: 0xc0000000018ff958
  Oops: Kernel access of bad area, sig: 11 [#1]
  ...
  NIP:  c0000000018ff958 LR: c0000000018ff930 CTR: c0000000009c0790
  REGS: c00000005f2e7790 TRAP: 0300   Tainted: G              K      (6.14.0+)
  MSR:  8000000000009033 <SF,EE,ME,IR,DR,RI,LE>  CR: 2822880b  XER: 20040000
  CFAR: c0000000008addc0 DAR: c0000000000f9078 DSISR: 0a000000 IRQMASK: 1
  GPR00: c0000000018f2584 c00000005f2e7a30 c00000000280a900 c000000017ffa488
  GPR04: 0000000000000008 0000000000000000 c0000000018f24fc 000000000000000d
  GPR08: fffffffffffe0000 000000000000000d 0000000000000000 0000000000008000
  GPR12: c0000000009c0790 c000000017ffa480 c00000005f2e7c78 c0000000000f9070
  GPR16: c00000005f2e7c90 0000000000000000 0000000000000000 0000000000000000
  GPR20: 0000000000000000 c00000005f3efa80 c00000005f2e7c60 c00000005f2e7c88
  GPR24: c00000005f2e7c60 0000000000000001 c0000000000f9078 0000000000000000
  GPR28: 00007fff97960000 c000000017ffa480 0000000000000000 c0000000000f9078
  ...
  Call Trace:
    check_heap_object+0x34/0x390 (unreliable)
  __mutex_unlock_slowpath.isra.0+0xe4/0x230
  seq_read_iter+0x430/0xa90
  proc_reg_read_iter+0xa4/0x200
  vfs_read+0x41c/0x510
  ksys_read+0xa4/0x190
  system_call_exception+0x1d0/0x440
  system_call_vectored_common+0x15c/0x2ec

Fix it by restoring r15 always.

## Which versions are affected by CVE-2025-38233?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2025-38233?

Apply the vendor's patch.

## Is CVE-2025-38233 being exploited?

There is no known exploitation of CVE-2025-38233 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-2025-38233 and fix it if it is affected.

What it is: CVE-2025-38233 is a high-severity memory corruption vulnerability in Linux kernel, published on 4 Jul 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-2025-38233 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-2025-38233/ (Markdown: https://insights.sbomify.com/CVE-2025-38233/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-38233
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-38233
- OSV: https://osv.dev/vulnerability/CVE-2025-38233

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-38233/
Summaries are generated and may contain mistakes; the official description above is the record.