SB2026042594 - Out-of-bounds write in Linux kernel net usb driver
Published: April 25, 2026
Security Bulletin ID
SB2026042594
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Physical access
Highest impact
Denial of service
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 vulnerability.
1) Out-of-bounds write (CVE-ID: CVE-2026-31623)
CWE-ID: CWE-787 - Out-of-bounds write
CVSSv4: CVSS:4.0/AV:P/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
The vulnerability allows an attacker with physical access to cause a denial of service.
The vulnerability exists due to an out-of-bounds write in rx_complete() in the cdc-phonet driver when processing bulk transfers from a malicious USB device claiming to be a CDC Phonet modem. An attacker with physical access can send an unbounded sequence of full-page bulk transfers to cause a denial of service.
Remediation
Install update from vendor's website.