CVE-2026-98612net: usb: catc: bound the RX packet length in catc_rx_done()

Official description

In the Linux kernel, the following vulnerability has been resolved: net: usb: catc: bound the RX packet length in catc_rx_done() catc_rx_done() walks a multi-packet URB, reading a two-byte length from each packet header. Its bound, pkt_len > urb->actual_length, ignores the header offset and compares against the whole transfer rather than the bytes left from pkt_start, so a crafted packet header makes skb_copy_to_linear_data() read past the buffer. A length below ETH_HLEN is also accepted, including zero, and eth_type_trans() then reads a MAC header from the uninitialised tailroom of a shorter skb. The is_f5u011 branch takes its length straight from the transfer, so a zero-length URB reaches the same path. Track the bytes remaining from the current packet, and reject a header that does not fit, a length past what is left, and a length below an Ethernet header. A transfer shorter than an Ethernet header, including a zero-length one, previously became a runt skb passed to netif_rx() and counted as received; it is now counted in rx_length_errors and ends the walk.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/3942557938f846e7481f6ccb2b41ccbdee61baa1
• https://git.kernel.org/stable/c/2f87bbd5a7bf6ee79d598f7e22cf77810d29ae87
• https://git.kernel.org/stable/c/4cc0a8eb2f9336cfa3e4ac329bc5585ca970ced3
• https://git.kernel.org/stable/c/21e206dd88b3de6e36bb607dec3797c59bc3007b
• https://git.kernel.org/stable/c/801e21cf7dd6bcee31db907625d5045f21c9c1d9
• https://git.kernel.org/stable/c/dd9c6f8f05170223edec2dac476606cd40d9acb7
• https://git.kernel.org/stable/c/9d4be026bdff2c1da7b6c7e01c0a47f2df409e97
• https://git.kernel.org/stable/c/9d565b6b72fe3f41fd43636e143072848105189f