FastNetMon Community Edition up to 1.2.9 Configuration Parameter src/packet_storage.hpp allocate_buffer buffer_size_in_packets integer overflow

Summaryinfo

A vulnerability categorized as problematic has been discovered in FastNetMon Community Edition up to 1.2.9. The impacted element is the function allocate_buffer of the file src/packet_storage.hpp of the component Configuration Parameter Handler. Such manipulation of the argument buffer_size_in_packets leads to integer overflow. This vulnerability is uniquely identified as CVE-2026-48690. No exploit exists.

Detailsinfo

A vulnerability was found in FastNetMon Community Edition up to 1.2.9 and classified as problematic. Affected by this issue is the function allocate_buffer of the file src/packet_storage.hpp of the component Configuration Parameter Handler. The manipulation of the argument buffer_size_in_packets with an unknown input leads to a integer overflow vulnerability. Using CWE to declare the problem leads to CWE-190. The product performs a calculation that can produce an integer overflow or wraparound, when the logic assumes that the resulting value will always be larger than the original value. This can introduce other weaknesses when the calculation is used for resource management or execution control. Impacted is confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is available at github.com. This vulnerability is handled as CVE-2026-48690 since 05/22/2026. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 05/26/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Vendor

• FastNetMon

Name

• Community Edition

Version

• 1.2.0
• 1.2.1
• 1.2.2
• 1.2.3
• 1.2.4
• 1.2.5
• 1.2.6
• 1.2.7
• 1.2.8
• 1.2.9

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CPE 2.2info

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