usb: atm: cxacru: fix a flaw in existing endpoint checks (CVE-2025-21916)

Summary

usb: atm: cxacru: fix a flaw in existing endpoint checks

Original description

The description as published by the source.

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:

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…

Source: OSV.dev (Open Source Vulnerabilities) NVD OSV

Affected packages

Linux Kernel

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"5.4.291"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.5.0"},{"fixed":"5.10.235"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.179"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.131"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.83"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.19"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.10.0"},{"fixed":"6.13.7"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

BellSoft Alpaquita BELL-CVE-2025-21916 linux-lts Fixed in: 6.1.131-r0
Debian DEBIAN-CVE-2025-21916 linux Fixed in: 5.10.237-1
Ubuntu UBUNTU-CVE-2025-21916 linux-aws

Summary

Original description

Affected packages

Fix status by distribution

References