Out-of-bounds write in FreeBSD - CVE-2026-101307
Published: October 14, 2026
Vulnerability identifier: #VU155795
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-101307
CWE-ID: CWE-787
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to an out-of-bounds write in the RACK stack's path capacity measurement (PCM) module when a 16-bit allocation counter wraps to zero during sample array expansion. A remote attacker can send a sufficient number of ACKs on an established TCP connection to cause a denial of service.
Exploitation requires the tcp_rack.ko kernel module to be loaded and the target connection to use the RACK stack.
Affected software
FreeBSD
How to mitigate CVE-2026-101307
Install security update from vendor's website.