CVE-2026-48690 Affecting fastnetmon package, versions *


Severity

Recommended
low

Based on Debian security rating.

Threat Intelligence

EPSS
0.12% (2nd percentile)

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  • Snyk IDSNYK-DEBIAN12-FASTNETMON-17089124
  • published29 May 2026
  • disclosed26 May 2026

Introduced: 26 May 2026

CVE-2026-48690  (opens in a new tab)

How to fix?

There is no fixed version for Debian:12 fastnetmon.

NVD Description

Note: Versions mentioned in the description apply only to the upstream fastnetmon package and not the fastnetmon package as distributed by Debian. See How to fix? for Debian:12 relevant fixed versions and status.

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 Base Scores

version 3.1