ax25: Fix reference count leak issues of ax25_dev

Summary

In the Linux kernel, the following vulnerability has been resolved: ax25: Fix reference count leak issues of ax25_dev The ax25_addr_ax25dev() and ax25_dev_device_down() exist a reference count leak issue of the object "ax25_dev". Memory leak issue in ax25_addr_ax25dev(): The reference count of the object "ax25_dev" can be increased multiple times in ax25_addr_ax25dev(). This will cause a memory leak. Memory leak issues in ax25_dev_device_down(): The reference count of ax25_dev is set to 1 in ax25_dev_device_up() and then increase the reference count when ax25_dev is added to ax25_dev_list. As a result, the reference count of ax25_dev is 2. But when the device is shutting down. The ax25_dev_device_down() drops the reference count once or twice depending on if we goto unlock_put or not, which will cause memory leak. As for the issue of ax25_addr_ax25dev(), it is impossible for one pointer to be on a list twice. So add a break in ax25_addr_ax25dev(). As for the issue of ax25_dev_device_down(), increase the reference count of ax25_dev once in ax25_dev_device_up() and decrease the reference count of ax25_dev after it is removed from the ax25_dev_list.

Timeline

1. Jun 19, 2024, 1:48 PM UTCCVE published
2. Sep 10, 2024, 5:13 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: no · Technical impact: partial

3. May 23, 2026, 3:49 PM UTCRecord last updated

Affected versions

• Linux Linux

  From 4.14.277 · fixed in 4.15; From 4.19.240 · fixed in 4.20; From 5.4.190 · fixed in 5.5; From 5.10.112 · fixed in 5.11; From 5.15.35 · fixed in 5.16

• Linux Linux

  5.17

References 5