# CVE-2025-37960: memblock: Accept allocated memory before use in memblock_double_array()

> A Linux kernel bug causes a crash during boot in SNP guests if memory is not accepted before use, requiring a patch to fix.

- **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:** 20 May 2025
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2025-37960, DEBIAN-CVE-2025-37960, GHSA-h279-pjhh-9hgj, ROOT-OS-UBUNTU-2404-CVE-2025-37960, UBUNTU-CVE-2025-37960

## What is CVE-2025-37960?

CVE-2025-37960 is a medium-severity vulnerability in Linux kernel, published on 20 May 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:

memblock: Accept allocated memory before use in memblock_double_array()

When increasing the array size in memblock_double_array() and the slab
is not yet available, a call to memblock_find_in_range() is used to
reserve/allocate memory. However, the range returned may not have been
accepted, which can result in a crash when booting an SNP guest:

  RIP: 0010:memcpy_orig+0x68/0x130
  Code: ...
  RSP: 0000:ffffffff9cc03ce8 EFLAGS: 00010006
  RAX: ff11001ff83e5000 RBX: 0000000000000000 RCX: fffffffffffff000
  RDX: 0000000000000bc0 RSI: ffffffff9dba8860 RDI: ff11001ff83e5c00
  RBP: 0000000000002000 R08: 0000000000000000 R09: 0000000000002000
  R10: 000000207fffe000 R11: 0000040000000000 R12: ffffffff9d06ef78
  R13: ff11001ff83e5000 R14: ffffffff9dba7c60 R15: 0000000000000c00
  memblock_double_array+0xff/0x310
  memblock_add_range+0x1fb/0x2f0
  memblock_reserve+0x4f/0xa0
  memblock_alloc_range_nid+0xac/0x130
  memblock_alloc_internal+0x53/0xc0
  memblock_alloc_try_nid+0x3d/0xa0
  swiotlb_init_remap+0x149/0x2f0
  mem_init+0xb/0xb0
  mm_core_init+0x8f/0x350
  start_kernel+0x17e/0x5d0
  x86_64_start_reservations+0x14/0x30
  x86_64_start_kernel+0x92/0xa0
  secondary_startup_64_no_verify+0x194/0x19b

Mitigate this by calling accept_memory() on the memory range returned
before the slab is available.

Prior to v6.12, the accept_memory() interface used a 'start' and 'end'
parameter instead of 'start' and 'size', therefore the accept_memory()
call must be adjusted to specify 'start + size' for 'end' when applying
to kernels prior to v6.12.

## Which versions are affected by CVE-2025-37960?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2025-37960?

Apply the vendor's patch.

## Is CVE-2025-37960 being exploited?

There is no known exploitation of CVE-2025-37960 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-2025-37960 and fix it if it is affected.

What it is: CVE-2025-37960 is a medium-severity vulnerability in Linux kernel, published on 20 May 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-2025-37960 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-2025-37960/ (Markdown: https://insights.sbomify.com/CVE-2025-37960/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-37960
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-37960
- OSV: https://osv.dev/vulnerability/CVE-2025-37960

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-37960/
Summaries are generated and may contain mistakes; the official description above is the record.