cbcvebase.
CVE-2025-68245
published 2025-12-16

CVE-2025-68245: In the Linux kernel, the following vulnerability has been resolved: net: netpoll: fix incorrect refcount handling causing incorrect cleanup commit efa95b01da18…

PriorityP421high7.8
EPSS
0.18%
7.5th percentile
In the Linux kernel, the following vulnerability has been resolved: net: netpoll: fix incorrect refcount handling causing incorrect cleanup commit efa95b01da18 ("netpoll: fix use after free") incorrectly ignored the refcount and prematurely set dev->npinfo to NULL during netpoll cleanup, leading to improper behavior and memory leaks. Scenario causing lack of proper cleanup: 1) A netpoll is associated with a NIC (e.g., eth0) and netdev->npinfo is allocated, and refcnt = 1 - Keep in mind that npinfo is shared among all netpoll instances. In this case, there is just one. 2) Another netpoll is also associated with the same NIC and npinfo->refcnt += 1. - Now dev->npinfo->refcnt = 2; - There is just one npinfo associated to the netdev. 3) When the first netpolls goes to clean up: - The first cleanup succeeds and clears np->dev->npinfo, ignoring refcnt. - It basically calls `RCU_INIT_POINTER(np->dev->npinfo, NULL);` - Set dev->npinfo = NULL, without proper cleanup - No ->ndo_netpoll_cleanup() is either called 4) Now the second target tries to clean up - The second cleanup fails because np->dev->npinfo is already NULL. * In this case, ops->ndo_netpoll_cleanup() was never called, and the skb pool is not cleaned as well (for the second netpoll instance) - This leaks npinfo and skbpool skbs, which is clearly reported by kmemleak. Revert commit efa95b01da18 ("netpoll: fix use after free") and adds clarifying comments emphasizing that npinfo cleanup should only happen once the refcount reaches zero, ensuring stable and correct netpoll behavior.

Affected

29 ranges· showing 25
VendorProductVersion rangeFixed in
debianlinux< linux 6.1.159-1 (bookworm)linux 6.1.159-1 (bookworm)
debianlinux-6.1< linux 6.1.159-1 (bookworm)linux 6.1.159-1 (bookworm)
linuxlinux
linuxlinux>= efa95b01da18ad22af62f6d99a3243f3be8fd264 < 8e6a50edad11e3e1426e4c29e7aa6201f3468ac28e6a50edad11e3e1426e4c29e7aa6201f3468ac2
linuxlinux>= efa95b01da18ad22af62f6d99a3243f3be8fd264 < 9b0bb18b4b9dc017c1825a2c5e763615e34a15939b0bb18b4b9dc017c1825a2c5e763615e34a1593
linuxlinux>= efa95b01da18ad22af62f6d99a3243f3be8fd264 < 890472d6fbf062e6de7fdd56642cb305ab79d669890472d6fbf062e6de7fdd56642cb305ab79d669
linuxlinux>= efa95b01da18ad22af62f6d99a3243f3be8fd264 < 4afd4ebbad52aa146838ec23082ba393e426a2bb4afd4ebbad52aa146838ec23082ba393e426a2bb
linuxlinux>= efa95b01da18ad22af62f6d99a3243f3be8fd264 < c645693180a98606c430825223d2029315d85e9dc645693180a98606c430825223d2029315d85e9d
linuxlinux>= efa95b01da18ad22af62f6d99a3243f3be8fd264 < c79a6d9da29219616b118a3adce9a14cd30f9bd0c79a6d9da29219616b118a3adce9a14cd30f9bd0
linuxlinux>= efa95b01da18ad22af62f6d99a3243f3be8fd264 < 9a51b5ccd1c79afec1c03a4e1e6688da525975569a51b5ccd1c79afec1c03a4e1e6688da52597556
linuxlinux>= efa95b01da18ad22af62f6d99a3243f3be8fd264 < 49c8d2c1f94cc2f4d1a108530d7ba52614b874c249c8d2c1f94cc2f4d1a108530d7ba52614b874c2
linuxlinux_kernel>= 0 < 5.10.247-15.10.247-1
linuxlinux_kernel>= 0 < 6.1.159-16.1.159-1
linuxlinux_kernel>= 0 < 6.12.63-16.12.63-1
linuxlinux_kernel>= 0 < 6.17.9-16.17.9-1
linuxlinux_kernel>= 0 < 5.15.0-173.1835.15.0-173.183
linuxlinux_kernel>= 0 < 6.8.0-106.1066.8.0-106.106
linuxlinux_kernel>= 0 < 6.17.0-14.146.17.0-14.14
linuxlinux_kernel>= 3.17.0 < 5.4.3025.4.302
linuxlinux_kernel>= 5.11.0 < 5.15.1975.15.197
linuxlinux_kernel>= 5.16.0 < 6.1.1596.1.159
linuxlinux_kernel>= 5.5.0 < 5.10.2475.10.247
linuxlinux_kernel>= 6.13.0 < 6.17.96.17.9
linuxlinux_kernel>= 6.2.0 < 6.6.1176.6.117
linuxlinux_kernel>= 6.7.0 < 6.12.596.12.59

CVSS provenance

osv7.8HIGH
vendor_ubuntu7.8HIGH
vendor_redhat6.1MEDIUM
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