CVE-2025-39854

In the Linux kernel, the following vulnerability has been resolved:

ice: fix NULL access of tx->in_use in ice_ll_ts_intr

Recent versions of the E810 firmware have support for an extra interrupt to handle report of the low latency Tx timestamps coming from the specialized low latency firmware interface. Instead of polling the registers, software can wait until the low latency interrupt is fired.

This logic makes use of the Tx timestamp tracking structure, ice_ptp_tx, as it uses the same ready bitmap to track which Tx timestamps complete.

Unfortunately, the ice_ll_ts_intr() function does not check if the tracker is initialized before its first access. This results in NULL dereference or use-after-free bugs similar to the issues fixed in the ice_ptp_ts_irq() function.

Fix this by only checking the in_use bitmap (and other fields) if the tracker is marked as initialized. The reset flow will clear the init field under lock before it tears the tracker down, thus preventing any use-after-free or NULL access.

Weakness

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.

Affected Software

Potential Mitigations

References

• https://git.kernel.org/stable/c/2cde98a02da958357fe240a6ba269b69d913b6ba
• https://git.kernel.org/stable/c/923c267bdbb64f65bc1149d184efcf8b047d7d64
• https://git.kernel.org/stable/c/f6486338fde3f04ed0ec59fe67a69a208c32734f