CVE-2025-21916

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 endpoints 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_probe_device+0x50/0x430 drivers/base/dd.c:830 …

Affected Software

References

• https://git.kernel.org/stable/c/197e78076c5ecd895f109158c4ea2954b9919af6
• https://git.kernel.org/stable/c/319529e0356bd904528c64647725a2272d297c83
• https://git.kernel.org/stable/c/903b80c21458bb1e34c3a78c5fdc553821e357f8
• https://git.kernel.org/stable/c/a0475a885d69849b1ade38add6d64338dfa83a8f
• https://git.kernel.org/stable/c/bf4409f84023b52b5e9b36c0a071a121eee42138
• https://git.kernel.org/stable/c/c90aad369899a607cfbc002bebeafd51e31900cd
• https://git.kernel.org/stable/c/cfc295f7cccf66cbd5123416bcf1bee2e1bd37de
• https://git.kernel.org/stable/c/dcd592ab9dd8a2bfc36e75583b9006db2a77ec24