CVE-2026-31623

Description

In the Linux kernel, the following vulnerability has been resolved: net: usb: cdc-phonet: fix skb frags[] overflow in rx_complete() A malicious USB device claiming to be a CDC Phonet modem can overflow the skb_shared_info->frags[] array by sending an unbounded sequence of full-page bulk transfers. Drop the skb and increment the length error when the frag limit is reached. This matches the same fix that commit f0813bcd2d9d ("net: wwan: t7xx: fix potential skb->frags overflow in RX path") did for the t7xx driver.

CVSS v3.1 Score

5.5

MEDIUM

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS — Exploit Prediction

0.0001

Probability of exploitation

0.02%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-120 CWE-120

Affected Products

Vendor	Product	Versions
linux	linux_kernel	2.6.31 — 6.6.136
linux	linux_kernel	6.7 — 6.12.83
linux	linux_kernel	6.13 — 6.18.24
linux	linux_kernel	6.19 — 6.19.14
linux	linux_kernel	7.0 — 7.0.1

References

Advisories & Patches

https://git.kernel.org/stable/c/600dc40554dc5ad1e6f3af51f700228033f43ea7 https://git.kernel.org/stable/c/9989938d13cc5ba8447eeed5a61acfcf61bc6801 https://git.kernel.org/stable/c/a23b1b1aaf41e174181d5853a70e65d4d01e648c https://git.kernel.org/stable/c/c183d5775129a0a7495bd61a6e57ec230dcf01e5 https://git.kernel.org/stable/c/d4e1946bea8d6441835eb3fd09b19237ba366a6f https://git.kernel.org/stable/c/ebf75c6301c4972a87542ebf2d994c6391eb5d46

Frequently Asked Questions

What is CVE-2026-31623? +

In the Linux kernel, the following vulnerability has been resolved: net: usb: cdc-phonet: fix skb frags[] overflow in rx_complete() A malicious USB device claiming to be a CDC Phonet modem can overflow the skb_shared_info->frags[] array by sending an unbounded sequence of full-page bulk transfers. Drop the skb and increment the length error when the frag limit is reached. This matches the same fix that commit f0813bcd2d9d ("net: wwan: t7xx: fix potential skb->frags overflow in RX path") did for the t7xx driver. It has a CVSS v3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2026-31623? +

CVE-2026-31623 has a CVSS v3.1 score of 5.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0001, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-31623? +

CVE-2026-31623 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-31623? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

Related Vulnerabilities

CVE-2026-27820

zlib is a Ruby interface for the zlib compression/decompression library. Versions 3.0.0 and below, 3.1.0, 3.1.1, 3.2.0 and 3.2.1 contain …

CVE-2024-13503

Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') vulnerability in Newtec NTC2218, NTC2250, NTC2299 on Linux, PowerPC, ARM …

CVE-2024-6199

An unauthenticated attacker on the WAN interface, with the ability to intercept Dynamic DNS (DDNS) traffic between DDNS services and …

CVE-2024-6198

The device exposes a web interface on ports TCP/3030 and TCP/9882. This web service runs lighttpd, which implements the “SNORE” …

CVE-2025-6151

A vulnerability has been found in TP-Link TL-WR940N V4 and TL-WR841N V11. Affected by this issue is some unknown functionality …

CVE-2025-34106

A buffer overflow vulnerability exists in PDF Shaper versions 3.5 and 3.6 when converting a crafted PDF file to an …