CVE-2026-31616

Medium

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").

SeverityMedium
CVSS5.5
Exploit probability—
ProductLinux Kernel
PublishedApr 24, 2026
First seenApr 24, 2026

How to fix

Update
  • linux linux_kernel6.6.136, 6.12.83, 6.18.24, 6.19.14, 7.0.1 or later

Affected products

ProductAffected versionsFixed in
linux linux_kernel2.6.32 ≤ v < 6.6.136, 6.7 ≤ v < 6.12.83, 6.13 ≤ v < 6.18.24, 6.19 ≤ v < 6.19.14, 7.0 ≤ v < 7.0.16.6.136, 6.12.83, 6.18.24, 6.19.14, 7.0.1

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