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 ...
Conclusion & alert: CVE-2025-21916 is rated Low Risk (24.5/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.03%). Mandatory action: Monitor for updates and reassess as exploit intelligence or EPSS changes.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2026-05-11 | 0.11% | 0.03% | -0.08% |
| 2 | 2026-01-26 | 0.03% | 0.11% | +0.08% |
| 3 | 2025-11-01 | — | 0.03% | — |
Full EPSS history (11 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 5.5 | 3.1 | MEDIUM |
|
1.8 | 3.6 | [email protected] |
| vendor | priority | summary | link |
|---|---|---|---|
debian
|
not yet assigned | CVE-2025-21916 not yet assigned priority: Debian including 2 source packages (linux, linux-6.1), 6 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 6. | https://security-tracker.debian.org/tracker/CVE-2025-21916 |
redhat
|
low | — | https://access.redhat.com/security/cve/CVE-2025-21916 |
suse
|
medium | — | https://www.suse.com/security/cve/CVE-2025-21916/ |
ubuntu
|
medium | CVE-2025-21916 medium priority: Ubuntu including 158 source packages (linux, linux-allwinner-5.19, …), 1551 status rows across 10 suites (bionic, focal, jammy, noble, oracular, plucky, questing, trusty, upstream, xenial): DNE 1145, released 192, ignored 153, not-affected 41, needed 20. | https://ubuntu.com/security/CVE-2025-21916 |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| linux | linux_kernel | >= 4.19.317, < 4.20 | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| linux | linux_kernel | >= 5.4.279, < 5.4.291 | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| linux | linux_kernel | >= 5.10.221, < 5.10.235 | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| linux | linux_kernel | >= 5.15.162, < 5.15.179 | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| linux | linux_kernel | >= 6.1.97, < 6.1.131 | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| linux | linux_kernel | >= 6.6.37, < 6.6.83 | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| linux | linux_kernel | >= 6.9.8, < 6.10 | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| linux | linux_kernel | >= 6.10.1, < 6.12.19 | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| linux | linux_kernel | >= 6.13, < 6.13.7 | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| linux | linux_kernel | 6.10 | cpe:2.3:o:linux:linux_kernel:6.10:-:*:*:*:*:*:* |
| linux | linux_kernel | 6.10 | cpe:2.3:o:linux:linux_kernel:6.10:rc6:*:*:*:*:*:* |
| linux | linux_kernel | 6.10 | cpe:2.3:o:linux:linux_kernel:6.10:rc7:*:*:*:*:*:* |
| linux | linux_kernel | 6.14 | cpe:2.3:o:linux:linux_kernel:6.14:rc1:*:*:*:*:*:* |
| linux | linux_kernel | 6.14 | cpe:2.3:o:linux:linux_kernel:6.14:rc2:*:*:*:*:*:* |
| linux | linux_kernel | 6.14 | cpe:2.3:o:linux:linux_kernel:6.14:rc3:*:*:*:*:*:* |
| linux | linux_kernel | 6.14 | cpe:2.3:o:linux:linux_kernel:6.14:rc4:*:*:*:*:*:* |
| linux | linux_kernel | 6.14 | cpe:2.3:o:linux:linux_kernel:6.14:rc5:*:*:*:*:*:* |