Bug 2461529 (CVE-2026-31616) - CVE-2026-31616 kernel: usb: gadget: f_phonet: fix skb frags[] overflow in pn_rx_complete()
Summary: CVE-2026-31616 kernel: usb: gadget: f_phonet: fix skb frags[] overflow in pn_...
Keywords:
Status: NEW
Alias: CVE-2026-31616
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
unspecified
unspecified
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-04-24 15:06 UTC by OSIDB Bzimport
Modified: 2026-04-24 20:04 UTC (History)
2 users (show)

Fixed In Version:
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Description OSIDB Bzimport 2026-04-24 15:06:48 UTC
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").


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