# CVE-2023-54278: s390/vmem: split pages when debug pagealloc is enabled

> A kernel panic occurs during boot on s390 systems if debug pagealloc is enabled, causing a denial of service.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Not stated
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 30 Dec 2025
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2023-54278, DEBIAN-CVE-2023-54278, GHSA-wr38-v9r2-5hhw, UBUNTU-CVE-2023-54278

## What is CVE-2023-54278?

CVE-2023-54278 is a denial of service vulnerability in Linux, published on 30 Dec 2025. 

### Official description

In the Linux kernel, the following vulnerability has been resolved:

s390/vmem: split pages when debug pagealloc is enabled

Since commit bb1520d581a3 ("s390/mm: start kernel with DAT enabled")
the kernel crashes early during boot when debug pagealloc is enabled:

mem auto-init: stack:off, heap alloc:off, heap free:off
addressing exception: 0005 ilc:2 [#1] SMP DEBUG_PAGEALLOC
Modules linked in:
CPU: 0 PID: 0 Comm: swapper Not tainted 6.5.0-rc3-09759-gc5666c912155 #630
[..]
Krnl Code: 00000000001325f6: ec5600248064 cgrj %r5,%r6,8,000000000013263e
           00000000001325fc: eb880002000c srlg %r8,%r8,2
          #0000000000132602: b2210051     ipte %r5,%r1,%r0,0
          >0000000000132606: b90400d1     lgr %r13,%r1
           000000000013260a: 41605008     la %r6,8(%r5)
           000000000013260e: a7db1000     aghi %r13,4096
           0000000000132612: b221006d     ipte %r6,%r13,%r0,0
           0000000000132616: e3d0d0000171 lay %r13,4096(%r13)

Call Trace:
 __kernel_map_pages+0x14e/0x320
 __free_pages_ok+0x23a/0x5a8)
 free_low_memory_core_early+0x214/0x2c8
 memblock_free_all+0x28/0x58
 mem_init+0xb6/0x228
 mm_core_init+0xb6/0x3b0
 start_kernel+0x1d2/0x5a8
 startup_continue+0x36/0x40
Kernel panic - not syncing: Fatal exception: panic_on_oops

This is caused by using large mappings on machines with EDAT1/EDAT2. Add
the code to split the mappings into 4k pages if debug pagealloc is enabled
by CONFIG_DEBUG_PAGEALLOC_ENABLE_DEFAULT or the debug_pagealloc kernel
command line option.

## Which versions are affected by CVE-2023-54278?


## How do I fix CVE-2023-54278?

Apply the vendor's patch.

## Is CVE-2023-54278 being exploited?

There is no known exploitation of CVE-2023-54278 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-54278 and fix it if it is affected.

What it is: CVE-2023-54278 is a denial of service vulnerability in Linux, published on 30 Dec 2025. 
Exploitation: There is no known exploitation of CVE-2023-54278 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-2023-54278/ (Markdown: https://insights.sbomify.com/CVE-2023-54278/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-54278
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-54278
- OSV: https://osv.dev/vulnerability/CVE-2023-54278

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-54278/
Summaries are generated and may contain mistakes; the official description above is the record.