Vulnerability Description
FastNetMon Community Edition through 1.2.9 contains an integer overflow vulnerability in the packet capture buffer allocation. In src/packet_storage.hpp, the allocate_buffer() function computes memory_size_in_bytes as 'buffer_size_in_packets * (max_captured_packet_size + sizeof(fastnetmon_pcap_pkthdr_t)) + sizeof(fastnetmon_pcap_file_header_t)' using unsigned int (32-bit) arithmetic. With max_captured_packet_size=1500 and sizeof(fastnetmon_pcap_pkthdr_t)=16, each packet requires approximately 1516 bytes. If buffer_size_in_packets exceeds approximately 2,832,542, the multiplication overflows, resulting in a much smaller allocation than expected. Subsequent write_packet() calls then write past the allocated buffer, causing heap corruption. The buffer_size_in_packets value is derived from the ban_details_records_count configuration parameter, which is parsed using atoi() with no overflow checking.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Pavel-Odintsov | Fastnetmon | <= 1.2.9 |
Related Weaknesses (CWE)
References
- https://github.com/pavel-odintsov/fastnetmonProduct
- https://github.com/pavel-odintsov/fastnetmon/blob/master/src/packet_storage.hppProduct
- https://lorikeetsecurity.com/blog/fastnetmon-cve-2026-48690-packet-storage-integThird Party Advisory
FAQ
What is CVE-2026-48690?
CVE-2026-48690 is a vulnerability with a CVSS score of 7.1 (HIGH). FastNetMon Community Edition through 1.2.9 contains an integer overflow vulnerability in the packet capture buffer allocation. In src/packet_storage.hpp, the allocate_buffer() function computes memory...
How severe is CVE-2026-48690?
CVE-2026-48690 has been rated HIGH with a CVSS base score of 7.1/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-48690?
Check the references section above for vendor advisories and patch information. Affected products include: Pavel-Odintsov Fastnetmon.