CVE-2024-38602: ax25: Fix reference count leak issues of ax25_dev

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-06-19 · updated 2026-06-17

Description

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.

Affected products

Linux kernel: from 5.17 before 6.1.93; from 6.2 before 6.6.33; from 6.7 before 6.8.12; from 6.9 before 6.9.3 — fixed in 6.1.93, 6.6.33, 6.8.12, 6.9.3

How to fix

Upgrade to a fixed version: Linux kernel 6.1.93, 6.6.33, 6.8.12, 6.9.3. Check the vendor advisory for mitigations.

References

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