CVE-2025-21776: linux NULL Pointer Dereference
Vulnerability summary
CVE-2025-21776 is a medium (CVSS 5.5) NULL Pointer Dereference vulnerability in linux. EPSS estimates a 0.28% chance of exploitation in the next 30 days, higher than 19.2% of scored vulnerabilities.
Advisory lineage
Upstream 0 · Downstream 49 · Related 48Timeline
- 27-02-2025PublishedVulnerability first disclosed.
- 15-10-2026Last modifiedVulnerability information updated.
Description
In the Linux kernel, the following vulnerability has been resolved: USB: hub: Ignore non-compliant devices with too many configs or interfaces Robert Morris created a test program which can cause usb_hub_to_struct_hub() to dereference a NULL or inappropriate pointer: Oops: general protection fault, probably for non-canonical address 0xcccccccccccccccc: 0000 [#1] SMP DEBUG_PAGEALLOC PTI CPU: 7 UID: 0 PID: 117 Comm: kworker/7:1 Not tainted 6.13.0-rc3-00017-gf44d154d6e3d #14 Hardware name: FreeBSD BHYVE/BHYVE, BIOS 14.0 10/17/2021 Workqueue: usb_hub_wq hub_event RIP: 0010:usb_hub_adjust_deviceremovable+0x78/0x110 ... Call Trace: <TASK> ? die_addr+0x31/0x80 ? exc_general_protection+0x1b4/0x3c0 ? asm_exc_general_protection+0x26/0x30 ? usb_hub_adjust_deviceremovable+0x78/0x110 hub_probe+0x7c7/0xab0 usb_probe_interface+0x14b/0x350 really_probe+0xd0/0x2d0 ? __pfx___device_attach_driver+0x10/0x10 __driver_probe_device+0x6e/0x110 driver_probe_device+0x1a/0x90 __device_attach_driver+0x7e/0xc0 bus_for_each_drv+0x7f/0xd0 __device_attach+0xaa/0x1a0 bus_probe_device+0x8b/0xa0 device_add+0x62e/0x810 usb_set_configuration+0x65d/0x990 usb_generic_driver_probe+0x4b/0x70 usb_probe_device+0x36/0xd0 The cause of this error is that the device has two interfaces, and the hub driver binds to interface 1 instead of interface 0, which is where usb_hub_to_struct_hub() looks. We can prevent the problem from occurring by refusing to accept hub devices that violate the USB spec by having more than one configuration or interface.
CVSS metrics
3 scores · 3 sources · 1 version- OSV · UbuntuEcosystem advisory · calculated5.5MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- OSV · DebianEcosystem advisory · calculated5.5MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
0.28%
Chance of exploitation in the next 30 days
Percentile
19%
Versus all other CVEs
30-day change
+0.04 pp
From 0.24% on 19-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Ubuntu138 products
- linuxAll versions (No fix recorded) | < 5.4.0-216.236 | < 5.15.0-140.150 | < 6.8.0-78.78
- linux-allwinner-5.19All versions (No fix recorded)
- linux-awsAll versions (No fix recorded) | < 5.4.0-1146.156 | < 5.15.0-1084.91 | < 6.8.0-1035.37
- linux-aws-5.0All versions (No fix recorded)
- linux-aws-5.11All versions (No fix recorded)
Linux2 products
- linux≥ d2123fd9e1a56b8006986ed37e0aaf93ef0dd978, < 49f077106fa07919a6a6dda99bb490dd1d1a8218 | ≥ d2123fd9e1a56b8006986ed37e0aaf93ef0dd978, < d343fe0fad5c1d689775f2dda24a85ce98e29566 | ≥ d2123fd9e1a56b8006986ed37e0aaf93ef0dd978, < d3a67adb365cdfdac4620daf38a82e57ca45806c | ≥ d2123fd9e1a56b8006986ed37e0aaf93ef0dd978, < c3720b04df84b5459050ae4e03ec7d545652f897 | ≥ d2123fd9e1a56b8006986ed37e0aaf93ef0dd978, < e905a0fca7bff0855d312c16f71e60e1773b393e | ≥ d2123fd9e1a56b8006986ed37e0aaf93ef0dd978, < 62d8f4c5454dd39aded4f343720d1c5a1803cfef | ≥ d2123fd9e1a56b8006986ed37e0aaf93ef0dd978, < 5b9778e1fe715700993ce436c152dc3b7df0b490 | ≥ d2123fd9e1a56b8006986ed37e0aaf93ef0dd978, < 2240fed37afbcdb5e8b627bc7ad986891100e05d | 3.9
- linux_kernel< 6.1.129 | ≥ 6.2, < 6.6.79 | ≥ 6.7, < 6.12.16 | ≥ 6.13, < 6.13.4 | 6.14:rc1 | 6.14:rc2
Debian1 product
- linux< 6.1.129-1 | < 6.12.16-1
3 vendors · 141 products
