# CVE-2026-31616: usb: gadget: f_phonet: fix skb frags[] overflow in pn_rx_complete()

CVE-2026-31616 is fixed in 16 products on 1 platform, first by DEBIAN-CVE-2026-31616, released May 15, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-31616
- Priority: High
- CVSS: 7.1 (Important)
- EPSS: 0.0013
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Apr 24, 2026
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-31616

## 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").

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | dtb-aarch64 opensuse-leap 16.0 | 6.12.0-160000.37.1 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 |
| Linux | kernel-64kb opensuse-leap 16.0 | 6.12.0-160000.37.1 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 |
| Linux | kernel-64kb sles 15.7 | 6.4.0-150700.53.73.2 | [SUSE-SU-2026:3166-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-3166-1.md) | Jul 21, 2026 |
| Linux | kernel-64kb sles 16.0 | 6.12.0-160000.37.1 | [SUSE-SU-2026:23231-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23231-1.md) | Aug 11, 2026 |
| Linux | kernel-azure opensuse-leap 16.0 | 6.12.0-160000.37.1 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 |
| Linux | kernel-azure sles 15.7 | 6.4.0-150700.53.73.2 | [SUSE-SU-2026:3166-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-3166-1.md) | Jul 21, 2026 |
| Linux | kernel-azure sles 16.0 | 6.12.0-160000.37.1 | [SUSE-SU-2026:23231-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23231-1.md) | Aug 11, 2026 |
| Linux | kernel-default opensuse-leap 16.0 | 6.12.0-160000.37.1 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 |
| Linux | kernel-default sles 15.7 | 6.4.0-150700.53.73.2 | [SUSE-SU-2026:3166-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-3166-1.md) | Jul 21, 2026 |
| Linux | kernel-default sles 16.0 | 6.12.0-160000.37.1 | [SUSE-SU-2026:23237-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23237-1.md) | Aug 11, 2026 |
| Linux | kernel-default-base opensuse-leap 16.0 | 6.12.0-160000.37.1.160000.2.19 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 |
| Linux | kernel-default-base sles 15.7 | 6.4.0-150700.53.73.2.150700.17.41.4 | [SUSE-SU-2026:3166-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-3166-1.md) | Jul 21, 2026 |
| Linux | kernel-default-base sles 16.0 | 6.12.0-160000.37.1.160000.2.19 | [SUSE-SU-2026:23231-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23231-1.md) | Aug 11, 2026 |
| Linux | kernel-docs opensuse-leap 16.0 | 6.12.0-160000.37.1 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 |
| Linux | kernel-docs sles 15.7 | 6.4.0-150700.53.73.1 | [SUSE-SU-2026:3166-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-3166-1.md) | Jul 21, 2026 |
| Linux | kernel-docs sles 16.0 | 6.12.0-160000.37.1 | [SUSE-SU-2026:23231-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23231-1.md) | Aug 11, 2026 |
| Linux | kernel-kvmsmall opensuse-leap 16.0 | 6.12.0-160000.37.1 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 |
| Linux | kernel-kvmsmall sles 16.0 | 6.12.0-160000.37.1 | [SUSE-SU-2026:23231-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23231-1.md) | Aug 11, 2026 |
| Linux | kernel-livepatch-SLE15-SP7-RT_Update_18 sles 15.7 | 1-150700.1.5.1 | [SUSE-SU-2026:3130-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-3130-1.md) | Jul 20, 2026 |
| Linux | kernel-livepatch-SLE15-SP7_Update_19 sles 15.7 | 1-150700.15.3.4 | [SUSE-SU-2026:3166-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-3166-1.md) | Jul 21, 2026 |
| Linux | kernel-obs-build opensuse-leap 16.0 | 6.12.0-160000.37.1 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 |
| Linux | kernel-obs-build sles 15.7 | 6.4.0-150700.53.73.2 | [SUSE-SU-2026:3166-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-3166-1.md) | Jul 21, 2026 |
| Linux | kernel-obs-qa opensuse-leap 16.0 | 6.12.0-160000.37.1 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 |
| Linux | kernel-obs-qa sles 16.0 | 6.12.0-160000.37.1 | [SUSE-SU-2026:23231-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23231-1.md) | Aug 11, 2026 |
| Linux | kernel-rt opensuse-leap 16.0 | 6.12.0-160000.37.1 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 |
| Linux | kernel-source opensuse-leap 16.0 | 6.12.0-160000.37.1 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 |
| Linux | kernel-source sles 15.7 | 6.4.0-150700.53.73.1 | [SUSE-SU-2026:3166-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-3166-1.md) | Jul 21, 2026 |
| Linux | kernel-source sles 16.0 | 6.12.0-160000.37.1 | [SUSE-SU-2026:23231-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23231-1.md) | Aug 11, 2026 |
| Linux | kernel-syms opensuse-leap 16.0 | 6.12.0-160000.37.1 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 |
| Linux | kernel-syms sles 15.7 | 6.4.0-150700.53.73.1 | [SUSE-SU-2026:3166-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-3166-1.md) | Jul 21, 2026 |
| Linux | kernel-syms sles 16.0 | 6.12.0-160000.37.1 | [SUSE-SU-2026:23231-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23231-1.md) | Aug 11, 2026 |
| Linux | kernel-zfcpdump opensuse-leap 16.0 | 6.12.0-160000.37.1 | [OPENSUSE-SU-2026:21555-1](https://patchblox.com/security/data/fix/linux/opensuse-su-2026-21555-1.md) | Aug 12, 2026 |
| Linux | kernel-zfcpdump sles 15.7 | 6.4.0-150700.53.73.2 | [SUSE-SU-2026:3166-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-3166-1.md) | Jul 21, 2026 |
| Linux | kernel-zfcpdump sles 16.0 | 6.12.0-160000.37.1 | [SUSE-SU-2026:23231-1](https://patchblox.com/security/data/fix/linux/suse-su-2026-23231-1.md) | Aug 11, 2026 |
| Linux | linux Debian 12.15 (bookworm) | 6.1.176-1 | [DEBIAN-CVE-2026-31616](https://patchblox.com/security/data/fix/linux/debian-cve-2026-31616.md) | May 15, 2026 |
| Linux | linux Debian 13.5 (trixie) | 6.12.85-1 | [DEBIAN-CVE-2026-31616](https://patchblox.com/security/data/fix/linux/debian-cve-2026-31616.md) | May 15, 2026 |
| Linux | linux Debian 14 | 6.19.14-1 | [DEBIAN-CVE-2026-31616](https://patchblox.com/security/data/fix/linux/debian-cve-2026-31616.md) | May 15, 2026 |

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Data as of 2026-11-09T07:25:28Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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