CVE-2026-31616
type: TechArticle
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").
date published: 2026-04-24T15:16:40.870
license: https://creativecommons.org/publicdomain/zero/1.0/
source: https://nvd.nist.gov/vuln/detail/CVE-2026-31616
publisher: AI Analytics
source organization: NIST National Vulnerability Database
main entity: Thing
  additional type: Vulnerability
  score: 5.5
  severity: MEDIUM
keywords: CWE-401

AI Analytics
type: Organization