CVE-2026-64565

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

Input: ims-pcu - fix heap-buffer-overflow in ims_pcu_process_data()

The ims_pcu_process_data() processes incoming URB data byte by byte. However, it fails to check if the read_pos index exceeds IMS_PCU_BUF_SIZE.

If a malicious USB device sends a packet larger than IMS_PCU_BUF_SIZE, read_pos will increment indefinitely. Moreover, since read_pos is located immediately after read_buf, the attacker can overwrite read_pos itself to arbitrarily control the index.

This manipulated read_pos is subsequently used in ims_pcu_handle_response() to copy data into cmd_buf, leading to a heap buffer overflow.

Specifically, an attacker can overwrite the cmd_done.wait.head located at offset 136 relative to cmd_buf in the ims_pcu_handle_response(). Consequently, when the driver calls complete(&pcu->cmd_done), it triggers a control flow hijack by using the manipulated pointer.

Fix this by adding a bounds check for read_pos before writing to read_buf. If the packet is too long, discard it, log a warning, and reset the parser state.

[dtor: factor out resetting packet state, reset checksum as well]

Affected Software

References

• https://git.kernel.org/stable/c/40bbbf2e91fd60715525bf0405c67876af817edf
• https://git.kernel.org/stable/c/875115b82c295277b81b6dfee7debc725f44e854
• https://git.kernel.org/stable/c/ca9f8c09845fb8c51b6d447f6428eecd1b8b0a49
• https://git.kernel.org/stable/c/d03a740e087de7dcb2a26dc1123377bd3d1d84ca