CVE-2026-48690
FastNetMon Community Edition through 1.2.9 contains an integer overflow vulnerability in the...
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.
Attack profile
How easy it is to exploit
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- None
Exploit likelihood
What each source reports
NVD Score used
7.1
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.
- Record
CVE-2026-48690- CVSS 3.1
- 7.1 High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N - Weakness
- CWE-122, CWE-190
- Updated
- 2026-11-02
CVE List
7.1
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.
- Record
CVE-2026-48690- CVSS 3.1
- 7.1 High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N - Weakness
- CWE-190, CWE-122
- Updated
- 2026-11-02
EUVDEUVD-2026-31897
7.1
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.
- Record
EUVD-2026-31897- CVSS 3.1
- 7.1 High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-h9r4-jj3x-8857
7.1
FastNetMon Community Edition through 1.2.9 contains an integer overflow vulnerability in the...
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.
- Record
GHSA-h9r4-jj3x-8857- CVSS 3.1
- 7.1 High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N - Weakness
- CWE-122
- Updated
- 2026-11-02
OSV
7.1
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.
- Record
CVE-2026-48690- CVSS 3.1
- 7.1 High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N - Updated
- 2026-11-02
OSVDEBIAN-CVE-2026-48690
7.1
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.
- Record
DEBIAN-CVE-2026-48690- CVSS 3.1
- 7.1 High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N - Updated
- 2026-11-02
OSVUBUNTU-CVE-2026-48690
7.1
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.
- Record
UBUNTU-CVE-2026-48690- CVSS 3.1
- 7.1 High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N - Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
fastnetmonDebian:12 |
All versions, plus listed versions 1.2.4-21.2.4-2+deb12u11.2.5-11.2.5-21.2.5-2~bpo12+1 Show 9 moreShow less1.2.6-11.2.6-1~bpo12+11.2.7-11.2.7-1~bpo12+11.2.8+git20250911-11.2.8+git20250911-21.2.8-11.2.8-1~bpo12+11.2.9-1 |
None known |
fastnetmonDebian:13 |
before 1.2.9-0+deb13u1, plus listed versions 1.2.8+git20250911-11.2.8+git20250911-21.2.8-1 |
1.2.9-0+deb13u1 |
fastnetmonDebian:14 |
before 1.2.9-1, plus listed versions 1.2.8+git20250911-11.2.8+git20250911-21.2.8-1 |
1.2.9-1 |
fastnetmonUbuntu:18.04:LTS |
All versions, plus listed versions 1.1.3+dfsg-31.1.3+dfsg-41.1.3+dfsg-6build1 |
None known |
fastnetmonUbuntu:Pro:20.04:LTS |
All versions, plus listed versions 1.1.4-11.1.4-1build31.1.4-1build41.1.4-1build51.1.4-1ubuntu0.1~esm1 |
None known |
fastnetmonUbuntu:Pro:24.04:LTS |
All versions, plus listed versions 1.2.5-11.2.6-11.2.6-1build11.2.6-1build21.2.6-1build31.2.6-1build41.2.6-1ubuntu0.1~esm1 |
None known |
fastnetmonUbuntu:25.10 |
All versions, plus listed versions 1.2.8-1build11.2.8-1build21.2.8+git20250911-1 |
None known |
fastnetmonUbuntu:26.10 |
All versions, plus listed versions 1.2.8+git20250911-21.2.9-11.2.9-1build11.2.9-1build2 |
None known |
fastnetmonUbuntu:Pro:26.04:LTS |
All versions, plus listed versions 1.2.8+git20250911-11.2.8+git20250911-1build11.2.8+git20250911-1build21.2.8+git20250911-21.2.8+git20250911-2ubuntu0.1~esm1 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-48690 is a high vulnerability (CVSS 7.1) in Pavel-odintsov Fastnetmon, published May 26, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.12%, the 1st percentile. Fixed in fastnetmon 1.2.9-0+deb13u1.
References
github.com/pavel-odintsov/fastnetmon
github.com/pavel-odintsov/fastnetmon/blob/master/src/packet_storage.hpp
lorikeetsecurity.com/blog/fastnetmon-cve-2026-48690-packet-storage-integer-overflow
nvd.nist.gov/vuln/detail/CVE-2026-48690
github.com/advisories/GHSA-h9r4-jj3x-8857
github.com/CVEProject/cvelistV5/tree/main/cves/2026/48xxx/CVE-2026-48690.json