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Linux KernelOperating system · Linux

CVE-2025-21916

MEDIUM · 5.5 CVSS v3.1 Published 2025-04-01
Fix available
A fix is available. Upgrade to 4.20 / 5.4.291 or later.
See remediation →
57/100
Remediation priority · Elevated
Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
In the Linux kernel, the following vulnerability has been resolved: usb: atm: cxacru: fix a flaw in existing endpoint checks Syzbot once again identified a flaw in usb endpoint checking, see [1]. This time the issue stems from a commit authored by me (2eabb655a968 ("usb: atm: cxacru: fix endpoint checking in cxacru_bind()")). While using usb_find_common_endpoints() may usually be enough to discard devices with wrong endpoints, in this case one needs more than just finding and identifying the sufficient number of endpoints of correct types - one needs to check the endpoint's address as well. Since cxacru_bind() fills URBs with CXACRU_EP_CMD address in mind, switch the endpoint verification approach to usb_check_XXX_endpoints() instead to fix incomplete ep testing. [1] Syzbot report: usb 5-1: BOGUS urb xfer, pipe 3 != type 1 WARNING: CPU: 0 PID: 1378 at drivers/usb/core/urb.c:504 usb_submit_urb+0xc4e/0x18c0 drivers/usb/core/urb.c:503 ... RIP: 0010:usb_submit_urb+0xc4e/0x18c0 drivers/usb/core/urb.c:503 ... Call Trace: <TASK> cxacru_cm+0x3c8/0xe50 drivers/usb/atm/cxacru.c:649 cxacru_card_status drivers/usb/atm/cxacru.c:760 [inline] cxacru_bind+0xcf9/0x1150 drivers/usb/atm/cxacru.c:1223 usbatm_usb_probe+0x314/0x1d30 drivers/usb/atm/usbatm.c:1058 cxacru_usb_probe+0x184/0x220 drivers/usb/atm/cxacru.c:1377 usb_probe_interface+0x641/0xbb0 drivers/usb/core/driver.c:396 really_probe+0x2b9/0xad0 drivers/base/dd.c:658 __driver_probe_device+0x1a2/0x390 drivers/base/dd.c:800 driver_probe_device+0x50/0x430 drivers/base/dd.c:830 ...

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis

A detailed technical summary for this CVE is being prepared.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Linux KernelOperating system
Affected:>= 4.19.317, < 4.20>= 5.4.279, < 5.4.291>= 5.10.221, < 5.10.235>= 5.15.162, < 5.15.179>= 6.1.97, < 6.1.131>= 6.6.37, < 6.6.83>= 6.9.8, < 6.10>= 6.10.1, < 6.12.19>= 6.13, < 6.13.7= 6.10= 6.14

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

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

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 4.20 / 5.4.291 / 5.10.235 or later
Fixed in 4.205.4.2915.10.235
Vendor patch git.kernel.org →
Recommended fix High confidence

Linux kernel >= 4.20 (for 4.19.x), >= 5.4.291 (for 5.4.x), >= 5.10.235 (for 5.10.x), or >= 5.15.179 (for 5.15.x)

  1. Identify the currently running Linux kernel version using `uname -r`
  2. Determine which branch of the kernel you are running (e.g., 5.15.x, 5.10.x, 5.4.x, or 4.19.x)
  3. Upgrade to the fixed kernel version for your branch: for 4.19.x upgrade to >=4.20, for 5.4.x upgrade to >=5.4.291, for 5.10.x upgrade to >=5.10.235, for 5.15.x upgrade to >=5.15.179
  4. Reboot the system to load the new kernel
  5. Verify the kernel version after reboot with `uname -r` to confirm the patch is applied
  6. Alternatively, if using a distribution-provided kernel, apply the distribution's security update for CVE-2025-21916
Caveat Kernel upgrades may require system reboot and could introduce compatibility issues with custom kernel modules or specific hardware drivers; ensure backups and test in non-production environment first

Generated from the published advisory — verify against the referenced sources before acting.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-21916 in production — separate from our analysis above.

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