CVE-2026-48684
Out-of-Bounds Read in FastNetMon Community Edition
Publication date: 2026-05-26
Last updated on: 2026-05-26
Assigner: MITRE
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| fastnetmon | community_edition | to 1.2.9 (inc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-UNKNOWN |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
CVE-2026-48684 is a vulnerability in FastNetMon Community Edition (up to version 1.2.9) affecting the NetFlow v9 options template parser.
The issue occurs in the function process_netflow_v9_options_template(), where two loops parse length fields controlled by an attacker without proper bounds checking.
This lack of validation allows an attacker to cause out-of-bounds reads by sending a specially crafted UDP packet, leading to memory reads beyond the packet boundary.
How can this vulnerability impact me? :
This vulnerability can have several impacts including exposing sensitive data from memory, crashing the FastNetMon service, or causing type confusion in downstream consumers.
An attacker can exploit this by sending a single crafted UDP packet to the default NetFlow v9 port (2055), making it relatively easy to trigger.
How can this vulnerability be detected on my network or system? Can you suggest some commands?
This vulnerability can be detected by monitoring for suspicious or malformed UDP packets sent to the default NetFlow v9 port (2055), as the exploit involves a single crafted UDP packet with manipulated length fields.
You can use network packet capture and analysis tools such as tcpdump or Wireshark to capture UDP traffic on port 2055 and inspect for abnormal NetFlow v9 option templates.
- Use tcpdump to capture UDP packets on port 2055: tcpdump -i <interface> udp port 2055 -w capture.pcap
- Analyze the captured packets with Wireshark, focusing on NetFlow v9 option templates for irregular option_scope_length or option_length fields.
Additionally, monitoring FastNetMon logs for crashes or unusual behavior related to NetFlow v9 processing may indicate exploitation attempts.
What immediate steps should I take to mitigate this vulnerability?
Immediate mitigation steps include restricting access to the NetFlow v9 UDP port (2055) using firewall rules to block or limit incoming traffic from untrusted sources.
You can also bind the FastNetMon NetFlow v9 collector to a specific trusted network interface to reduce exposure.
If feasible, disable the NetFlow v9 collector feature in FastNetMon until a vendor fix is released.
These mitigations help prevent attackers from sending crafted UDP packets that trigger the out-of-bounds read vulnerability.
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
The vulnerability in FastNetMon Community Edition allows out-of-bounds reads that can potentially expose sensitive data or cause service crashes. Such exposure or disruption could impact compliance with standards like GDPR or HIPAA, which require protection of sensitive data and system availability. However, the provided information does not explicitly discuss compliance implications or regulatory impacts.