# CVE-2025-38558: usb: gadget: uvc: Initialize frame-based format color matching descriptor

> A local attacker can cause a kernel crash by configuring USB gadget settings without a color matching descriptor, leading to a null pointer dereference.

- **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:** 19 Aug 2025
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2025-38558, DEBIAN-CVE-2025-38558, GHSA-42jr-fvmf-q363, UBUNTU-CVE-2025-38558

## What is CVE-2025-38558?

CVE-2025-38558 is a medium-severity vulnerability in Linux kernel, published on 19 Aug 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:

usb: gadget: uvc: Initialize frame-based format color matching descriptor

Fix NULL pointer crash in uvcg_framebased_make due to uninitialized color
matching descriptor for frame-based format which was added in
commit f5e7bdd34aca ("usb: gadget: uvc: Allow creating new color matching
descriptors") that added handling for uncompressed and mjpeg format.

Crash is seen when userspace configuration (via configfs) does not
explicitly define the color matching descriptor. If color_matching is not
found, config_group_find_item() returns NULL. The code then jumps to
out_put_cm, where it calls config_item_put(color_matching);. If
color_matching is NULL, this will dereference a null pointer, leading to a
crash.

[    2.746440] Unable to handle kernel NULL pointer dereference at virtual address 000000000000008c
[    2.756273] Mem abort info:
[    2.760080]   ESR = 0x0000000096000005
[    2.764872]   EC = 0x25: DABT (current EL), IL = 32 bits
[    2.771068]   SET = 0, FnV = 0
[    2.771069]   EA = 0, S1PTW = 0
[    2.771070]   FSC = 0x05: level 1 translation fault
[    2.771071] Data abort info:
[    2.771072]   ISV = 0, ISS = 0x00000005, ISS2 = 0x00000000
[    2.771073]   CM = 0, WnR = 0, TnD = 0, TagAccess = 0
[    2.771074]   GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
[    2.771075] user pgtable: 4k pages, 39-bit VAs, pgdp=00000000a3e59000
[    2.771077] [000000000000008c] pgd=0000000000000000, p4d=0000000000000000, pud=0000000000000000
[    2.771081] Internal error: Oops: 0000000096000005 [#1] PREEMPT SMP
[    2.771084] Dumping ftrace buffer:
[    2.771085]    (ftrace buffer empty)
[    2.771138] CPU: 7 PID: 486 Comm: ln Tainted: G        W   E      6.6.58-android15
[    2.771139] Hardware name: Qualcomm Technologies, Inc. SunP QRD HDK (DT)
[    2.771140] pstate: 61400005 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--)
[    2.771141] pc : __uvcg_fill_strm+0x198/0x2cc
[    2.771145] lr : __uvcg_iter_strm_cls+0xc8/0x17c
[    2.771146] sp : ffffffc08140bbb0
[    2.771146] x29: ffffffc08140bbb0 x28: ffffff803bc81380 x27: ffffff8023bbd250
[    2.771147] x26: ffffff8023bbd250 x25: ffffff803c361348 x24: ffffff803d8e6768
[    2.771148] x23: 0000000000000004 x22: 0000000000000003 x21: ffffffc08140bc48
[    2.771149] x20: 0000000000000000 x19: ffffffc08140bc48 x18: ffffffe9f8cf4a00
[    2.771150] x17: 000000001bf64ec3 x16: 000000001bf64ec3 x15: ffffff8023bbd250
[    2.771151] x14: 000000000000000f x13: 004c4b40000f4240 x12: 000a2c2a00051615
[    2.771152] x11: 000000000000004f x10: ffffffe9f76b40ec x9 : ffffffe9f7e389d0
[    2.771153] x8 : ffffff803d0d31ce x7 : 000f4240000a2c2a x6 : 0005161500028b0a
[    2.771154] x5 : ffffff803d0d31ce x4 : 0000000000000003 x3 : 0000000000000000
[    2.771155] x2 : ffffffc08140bc50 x1 : ffffffc08140bc48 x0 : 0000000000000000
[    2.771156] Call trace:
[    2.771157]  __uvcg_fill_strm+0x198/0x2cc
[    2.771157]  __uvcg_iter_strm_cls+0xc8/0x17c
[    2.771158]  uvcg_streaming_class_allow_link+0x240/0x290
[    2.771159]  configfs_symlink+0x1f8/0x630
[    2.771161]  vfs_symlink+0x114/0x1a0
[    2.771163]  do_symlinkat+0x94/0x28c
[    2.771164]  __arm64_sys_symlinkat+0x54/0x70
[    2.771164]  invoke_syscall+0x58/0x114
[    2.771166]  el0_svc_common+0x80/0xe0
[    2.771168]  do_el0_svc+0x1c/0x28
[    2.771169]  el0_svc+0x3c/0x70
[    2.771172]  el0t_64_sync_handler+0x68/0xbc
[    2.771173]  el0t_64_sync+0x1a8/0x1ac

Initialize color matching descriptor for frame-based format to prevent
NULL pointer crash by mirroring the handling done for uncompressed and
mjpeg formats.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2025-38558?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2025-38558?

Apply the vendor's patch.

## Is CVE-2025-38558 being exploited?

There is no known exploitation of CVE-2025-38558 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-2025-38558 and fix it if it is affected.

What it is: CVE-2025-38558 is a medium-severity vulnerability in Linux kernel, published on 19 Aug 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-2025-38558 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-2025-38558/ (Markdown: https://insights.sbomify.com/CVE-2025-38558/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-38558
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-38558
- OSV: https://osv.dev/vulnerability/CVE-2025-38558

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-38558/
Summaries are generated and may contain mistakes; the official description above is the record.
