# CVE-2025-71134: mm/page_alloc: change all pageblocks migrate type on coalescing

> A logic error in Linux kernel page allocation causes inconsistent migration types, leading to kernel warnings and potential system instability or crashes.

- **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:** 14 Jan 2026
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2025-71134, DEBIAN-CVE-2025-71134, GHSA-wpqv-9qcp-f278, ROOT-OS-DEBIAN-13-CVE-2025-71134, UBUNTU-CVE-2025-71134

## What is CVE-2025-71134?

CVE-2025-71134 is a medium-severity denial of service vulnerability in Linux kernel, published on 14 Jan 2026. 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:

mm/page_alloc: change all pageblocks migrate type on coalescing

When a page is freed it coalesces with a buddy into a higher order page
while possible.  When the buddy page migrate type differs, it is expected
to be updated to match the one of the page being freed.

However, only the first pageblock of the buddy page is updated, while the
rest of the pageblocks are left unchanged.

That causes warnings in later expand() and other code paths (like below),
since an inconsistency between migration type of the list containing the
page and the page-owned pageblocks migration types is introduced.

[  308.986589] ------------[ cut here ]------------
[  308.987227] page type is 0, passed migratetype is 1 (nr=256)
[  308.987275] WARNING: CPU: 1 PID: 5224 at mm/page_alloc.c:812 expand+0x23c/0x270
[  308.987293] Modules linked in: algif_hash(E) af_alg(E) nft_fib_inet(E) nft_fib_ipv4(E) nft_fib_ipv6(E) nft_fib(E) nft_reject_inet(E) nf_reject_ipv4(E) nf_reject_ipv6(E) nft_reject(E) nft_ct(E) nft_chain_nat(E) nf_nat(E) nf_conntrack(E) nf_defrag_ipv6(E) nf_defrag_ipv4(E) nf_tables(E) s390_trng(E) vfio_ccw(E) mdev(E) vfio_iommu_type1(E) vfio(E) sch_fq_codel(E) drm(E) i2c_core(E) drm_panel_orientation_quirks(E) loop(E) nfnetlink(E) vsock_loopback(E) vmw_vsock_virtio_transport_common(E) vsock(E) ctcm(E) fsm(E) diag288_wdt(E) watchdog(E) zfcp(E) scsi_transport_fc(E) ghash_s390(E) prng(E) aes_s390(E) des_generic(E) des_s390(E) libdes(E) sha3_512_s390(E) sha3_256_s390(E) sha_common(E) paes_s390(E) crypto_engine(E) pkey_cca(E) pkey_ep11(E) zcrypt(E) rng_core(E) pkey_pckmo(E) pkey(E) autofs4(E)
[  308.987439] Unloaded tainted modules: hmac_s390(E):2
[  308.987650] CPU: 1 UID: 0 PID: 5224 Comm: mempig_verify Kdump: loaded Tainted: G            E       6.18.0-gcc-bpf-debug #431 PREEMPT
[  308.987657] Tainted: [E]=UNSIGNED_MODULE
[  308.987661] Hardware name: IBM 3906 M04 704 (z/VM 7.3.0)
[  308.987666] Krnl PSW : 0404f00180000000 00000349976fa600 (expand+0x240/0x270)
[  308.987676]            R:0 T:1 IO:0 EX:0 Key:0 M:1 W:0 P:0 AS:3 CC:3 PM:0 RI:0 EA:3
[  308.987682] Krnl GPRS: 0000034980000004 0000000000000005 0000000000000030 000003499a0e6d88
[  308.987688]            0000000000000005 0000034980000005 000002be803ac000 0000023efe6c8300
[  308.987692]            0000000000000008 0000034998d57290 000002be00000100 0000023e00000008
[  308.987696]            0000000000000000 0000000000000000 00000349976fa5fc 000002c99b1eb6f0
[  308.987708] Krnl Code: 00000349976fa5f0: c020008a02f2	larl	%r2,000003499883abd4
                          00000349976fa5f6: c0e5ffe3f4b5	brasl	%r14,0000034997378f60
                         #00000349976fa5fc: af000000		mc	0,0
                         >00000349976fa600: a7f4ff4c		brc	15,00000349976fa498
                          00000349976fa604: b9040026		lgr	%r2,%r6
                          00000349976fa608: c0300088317f	larl	%r3,0000034998800906
                          00000349976fa60e: c0e5fffdb6e1	brasl	%r14,00000349976b13d0
                          00000349976fa614: af000000		mc	0,0
[  308.987734] Call Trace:
[  308.987738]  [<00000349976fa600>] expand+0x240/0x270
[  308.987744] ([<00000349976fa5fc>] expand+0x23c/0x270)
[  308.987749]  [<00000349976ff95e>] rmqueue_bulk+0x71e/0x940
[  308.987754]  [<00000349976ffd7e>] __rmqueue_pcplist+0x1fe/0x2a0
[  308.987759]  [<0000034997700966>] rmqueue.isra.0+0xb46/0xf40
[  308.987763]  [<0000034997703ec8>] get_page_from_freelist+0x198/0x8d0
[  308.987768]  [<0000034997706fa8>] __alloc_frozen_pages_noprof+0x198/0x400
[  308.987774]  [<00000349977536f8>] alloc_pages_mpol+0xb8/0x220
[  308.987781]  [<0000034997753bf6>] folio_alloc_mpol_noprof+0x26/0xc0
[  308.987786]  [<0000034997753e4c>] vma_alloc_folio_noprof+0x6c/0xa0
[  308.987791]  [<0000034997775b22>] vma_alloc_anon_folio_pmd+0x42/0x240
[  308.987799]  [<000003499777bfea>] __do_huge_pmd_anonymous_page+0x3a/0x210
[  308.987804]  [<00000349976cb0
---truncated---

## Which versions are affected by CVE-2025-71134?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2025-71134?

Apply the vendor's patch.

## Is CVE-2025-71134 being exploited?

There is no known exploitation of CVE-2025-71134 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-2025-71134 and fix it if it is affected.

What it is: CVE-2025-71134 is a medium-severity denial of service vulnerability in Linux kernel, published on 14 Jan 2026. 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-2025-71134 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-2025-71134/ (Markdown: https://insights.sbomify.com/CVE-2025-71134/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-71134
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-71134
- OSV: https://osv.dev/vulnerability/CVE-2025-71134

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-71134/
Summaries are generated and may contain mistakes; the official description above is the record.