Skip to content
Fencer Vulns
high 7.1

CVE-2026-48690 json

FastNetMon Community Edition through 1.2.9 contains an integer overflow vulnerability in the packet capture buffer allocation.

published 2026-05-26 5 mo ago modified 2026-07-24 3 mo ago also EUVD-2026-31897

cvss
7.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 1%
public exploits
0
none known

Summary

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.

Patch / fix

  • fastnetmon Debian 13 1.2.9-0+deb13u1
  • fastnetmon Debian 14 1.2.9-1

debian advisories DEBIAN-CVE-2026-48690

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-48690 updated cvss 7.1

fastnetmon: integer overflow in the packet capture buffer allocation

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
5 mo ago

Exploit prediction

0.12% chance of exploitation in the next 30 days, higher than 1% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 7.1 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
NVD 3.1 7.1 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
CNA 3.1 7.1 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

Classification

Weakness
  • CWE-190 Integer Overflow or Wraparound
  • CWE-122 Heap-based Buffer Overflow

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.