CVE-2026-31616
Published: May 3, 2026Last modified: June 2, 2026
Description
In the Linux kernel, the following vulnerability has been resolved: usb: gadget: f_phonet: fix skb frags[] overflow in pn_rx_complete() A broken/bored/mean USB host can overflow the skb_shared_info->frags[] array on a Linux gadget exposing a Phonet function by sending an unbounded sequence of full-page OUT transfers. pn_rx_complete() finalizes the skb only when req->actual < req->length, where req->length is set to PAGE_SIZE by the gadget. If the host always sends exactly PAGE_SIZE bytes per transfer, fp->rx.skb will never be reset and each completion will add another fragment via skb_add_rx_frag(). Once nr_frags exceeds MAX_SKB_FRAGS (default 17), subsequent frag stores overwrite memory adjacent to the shinfo on the heap. Drop the skb and account a length error when the frag limit is reached, matching the fix applied in t7xx by commit f0813bcd2d9d ("net: wwan: t7xx: fix potential skb->frags overflow in RX path").
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score | 5.5 |
| Attack Vector | LOCAL |
| Attack complexity | LOW |
| Privileges required | LOW |
| User interaction | NONE |
| Scope | UNCHANGED |
| Confidentiality | NONE |
| Integrity impact | NONE |
| Availability impact | HIGH |
| Vector | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
Status
| Product | Release | Package | Status |
|---|---|---|---|
| Alpaquita Linux | 23 LTS | linux-lts | Fixed (6.1.175-r0) |
| 25 LTS | linux-lts | Fixed (6.12.85-r0) | |
| Stream | linux-lts | Fixed (6.12.85-r0) |
References
- https://git.kernel.org/stable/c/3d7f7e0c842242878c24b2facff8d6eda23ee1e9
- https://git.kernel.org/stable/c/4e476c25bfcab0535ba7c76a903ae77ca8747711
- https://git.kernel.org/stable/c/66f7471c4042e4eb300e30b5b9d87d1406862673
- https://git.kernel.org/stable/c/7424f0287da73d3d8c5fa5e9d25d26fce762708e
- https://git.kernel.org/stable/c/9ceff1251904901b0b4e5fe6350fcaffa368ce83
- https://git.kernel.org/stable/c/b5ec49fa198bd08967a3102bd41f53ccadce72c9
- https://git.kernel.org/stable/c/bd44ce09b9b569f49ed13e2d87d23d853fc7d6a7
- https://git.kernel.org/stable/c/c088d5dd2fffb4de1fb8e7f57751c8b82942180a
- https://git.kernel.org/stable/c/c9315ce9da3632c591666a29de82d3e92d46bec1