SB20260912372 - Integer underflow in Linux kernel net driver
Published: September 12, 2026
Security Bulletin ID
SB20260912372
CSH Severity
Low
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Local access
Highest impact
Data manipulation
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 vulnerability.
1) Integer underflow (CVE-ID: CVE-2026-81000)
CWE-ID: CWE-191 - Integer underflow
CVSSv4: 4.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N]
The vulnerability allows a local user to write packet data outside allocated memory.
The vulnerability exists due to an integer underflow in TUN and TAP interface handling in tun_get_user() when processing an oversized headroom request propagated by an OVS port. A local user can configure an OVS port to propagate an oversized headroom request to a TUN or TAP device to write packet data outside allocated memory.
Remediation
Install update from vendor's website.