Off-by-one in Tcpreplay - #VU139347
Published: July 24, 2026
Vulnerability identifier: #VU139347
CSH Severity: Low
CVSS v4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-193
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to cause a denial of service.
The vulnerability exists due to an off-by-one heap-based buffer overflow in the tcp_chaff fragroute module when processing an attacker-influenced fragroute rules file with a tcp_chaff directive. A remote user can supply a crafted rules file to cause a denial of service.
Exploitation requires tcprewrite to be built with libdnet/fragroute support and invoked with the --fragroute option against a pcap containing TCP traffic with payload data and the ACK flag set.
Affected software
Tcpreplay
Remediation
Install security update from vendor's website.
Tcpreplay - addressed in versions 4.5.5, 4.6.0 beta2