# CVE-2025-39907: mtd: rawnand: stm32_fmc2: avoid overlapping mappings on ECC buffer

> A memory corruption issue in the STM32 FMC2 NAND driver causes overlapping DMA mappings, leading to kernel warnings and potential system instability.

- **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:** 1 Oct 2025
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2025-39907, DEBIAN-CVE-2025-39907, GHSA-mrx7-jvx3-fwv3, ROOT-OS-DEBIAN-11-CVE-2025-39907, ROOT-OS-UBUNTU-2204-CVE-2025-39907, ROOT-OS-UBUNTU-2404-CVE-2025-39907, UBUNTU-CVE-2025-39907

## What is CVE-2025-39907?

CVE-2025-39907 is a medium-severity memory corruption vulnerability in Debian Debian Linux, published on 1 Oct 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:

mtd: rawnand: stm32_fmc2: avoid overlapping mappings on ECC buffer

Avoid below overlapping mappings by using a contiguous
non-cacheable buffer.

[    4.077708] DMA-API: stm32_fmc2_nfc 48810000.nand-controller: cacheline tracking EEXIST,
overlapping mappings aren't supported
[    4.089103] WARNING: CPU: 1 PID: 44 at kernel/dma/debug.c:568 add_dma_entry+0x23c/0x300
[    4.097071] Modules linked in:
[    4.100101] CPU: 1 PID: 44 Comm: kworker/u4:2 Not tainted 6.1.82 #1
[    4.106346] Hardware name: STMicroelectronics STM32MP257F VALID1 SNOR / MB1704 (LPDDR4 Power discrete) + MB1703 + MB1708 (SNOR MB1730) (DT)
[    4.118824] Workqueue: events_unbound deferred_probe_work_func
[    4.124674] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[    4.131624] pc : add_dma_entry+0x23c/0x300
[    4.135658] lr : add_dma_entry+0x23c/0x300
[    4.139792] sp : ffff800009dbb490
[    4.143016] x29: ffff800009dbb4a0 x28: 0000000004008022 x27: ffff8000098a6000
[    4.150174] x26: 0000000000000000 x25: ffff8000099e7000 x24: ffff8000099e7de8
[    4.157231] x23: 00000000ffffffff x22: 0000000000000000 x21: ffff8000098a6a20
[    4.164388] x20: ffff000080964180 x19: ffff800009819ba0 x18: 0000000000000006
[    4.171545] x17: 6361727420656e69 x16: 6c6568636163203a x15: 72656c6c6f72746e
[    4.178602] x14: 6f632d646e616e2e x13: ffff800009832f58 x12: 00000000000004ec
[    4.185759] x11: 00000000000001a4 x10: ffff80000988af58 x9 : ffff800009832f58
[    4.192916] x8 : 00000000ffffefff x7 : ffff80000988af58 x6 : 80000000fffff000
[    4.199972] x5 : 000000000000bff4 x4 : 0000000000000000 x3 : 0000000000000000
[    4.207128] x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff0000812d2c40
[    4.214185] Call trace:
[    4.216605]  add_dma_entry+0x23c/0x300
[    4.220338]  debug_dma_map_sg+0x198/0x350
[    4.224373]  __dma_map_sg_attrs+0xa0/0x110
[    4.228411]  dma_map_sg_attrs+0x10/0x2c
[    4.232247]  stm32_fmc2_nfc_xfer.isra.0+0x1c8/0x3fc
[    4.237088]  stm32_fmc2_nfc_seq_read_page+0xc8/0x174
[    4.242127]  nand_read_oob+0x1d4/0x8e0
[    4.245861]  mtd_read_oob_std+0x58/0x84
[    4.249596]  mtd_read_oob+0x90/0x150
[    4.253231]  mtd_read+0x68/0xac

## Which versions are affected by CVE-2025-39907?

It affects 2 products.


Products: Debian Debian Linux, Linux kernel.

## How do I fix CVE-2025-39907?

Apply the vendor's patch.

## Is CVE-2025-39907 being exploited?

There is no known exploitation of CVE-2025-39907 in the wild and no public exploit code.

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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-2025-39907 and fix it if it is affected.

What it is: CVE-2025-39907 is a medium-severity memory corruption vulnerability in Debian Debian Linux, published on 1 Oct 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-2025-39907 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-2025-39907/ (Markdown: https://insights.sbomify.com/CVE-2025-39907/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-39907
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-39907
- OSV: https://osv.dev/vulnerability/CVE-2025-39907

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-39907/
Summaries are generated and may contain mistakes; the official description above is the record.
