Out-of-bounds read in FastNetMon - #VU138932
Published: July 21, 2026
Vulnerability identifier: #VU138932
CSH Severity: High
CVSS v4: 8.8 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-125
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service and disclose sensitive information.
The vulnerability exists due to out-of-bounds read in the sFlow collector nested packet parser when processing a crafted sFlow v5 packet with an attacker-controlled header_size field. A remote attacker can send a specially crafted UDP packet to cause a denial of service and disclose sensitive information.
The issue occurs because the header_size field is trusted as the capture-length bound for nested Ethernet/IP/L4 parsing, causing bounds checks to use an attacker-inflated end pointer instead of the real buffer length.
Affected software
FastNetMon
Remediation
Cybersecurity Help is not aware of any official solution to address this vulnerability.