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CVE-2026-31616

usb: gadget: f_phonet: fix skb frags[] overflow in pn_rx_complete() PUBLISHED

Description (CNA)

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").

Affected (CNA)

Vendor / productVersions
Linux / Linuxaffected b91cd1440870f7a0649e570498b7b93caf9f781c before 3d7f7e0c842242878c24b2facff8d6eda23ee1e9; affected b91cd1440870f7a0649e570498b7b93caf9f781c before b5ec49fa198bd08967a3102bd41f53ccadce72c9; affected b91cd1440870f7a0649e570498b7b93caf9f781c before 7424f0287da73d3d8c5fa5e9d25d26fce762708e; affected b91cd1440870f7a0649e570498b7b93caf9f781c before 9ceff1251904901b0b4e5fe6350fcaffa368ce83; affected b91cd1440870f7a0649e570498b7b93caf9f781c before c9315ce9da3632c591666a29de82d3e92d46bec1; affected b91cd1440870f7a0649e570498b7b93caf9f781c before 4e476c25bfcab0535ba7c76a903ae77ca8747711; affected b91cd1440870f7a0649e570498b7b93caf9f781c before bd44ce09b9b569f49ed13e2d87d23d853fc7d6a7; affected b91cd1440870f7a0649e570498b7b93caf9f781c before 66f7471c4042e4eb300e30b5b9d87d1406862673; affected b91cd1440870f7a0649e570498b7b93caf9f781c before c088d5dd2fffb4de1fb8e7f57751c8b82942180a
Linux / Linuxaffected 2.6.32; unaffected 0 before 2.6.32; unaffected 5.10.258 through 5.10.*; unaffected 5.15.209 through 5.15.*; unaffected 6.1.175 through 6.1.*; unaffected 6.6.136 through 6.6.*; unaffected 6.12.83 through 6.12.*; unaffected 6.18.24 through 6.18.*; unaffected 6.19.14 through 6.19.*; unaffected 7.0.1 through 7.0.*; unaffected 7.1 through *

CWE

No CWE identifiers supplied.

References