CVE-2025-38558: linux kernel Null Dereference — Fix

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.

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CVSS v3.1 Score

5.5

MEDIUM

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Weakness Type (CWE)

CWE-476 CWE-476

Affected Products

Vendor	Product	Versions
linux	linux_kernel	6.13 — 6.15.10
linux	linux_kernel	6.16 — 6.16.1

References

Advisories & Patches

https://git.kernel.org/stable/c/323a80a1a5ace319a722909c006d5bdb2a35d273 https://git.kernel.org/stable/c/6db61c1aa23075eeee90e083ca3f6567a5635da6 https://git.kernel.org/stable/c/7f8576fc9d1a203d12474bf52710c7af68cae490

Frequently Asked Questions

What is CVE-2025-38558? +

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. It has a CVSS v3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2025-38558? +

CVE-2025-38558 has a CVSS v3.1 score of 5.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2025-38558? +

CVE-2025-38558 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-38558? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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