CVE-2026-48690

What it is

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.

At a glance

Exploitability

Can be exploited locally on the machine with a low-privilege account. High risk of data exposure, data tampering.

Exploit odds

0.1% chance of exploitation in the next 30 days (EPSS).

Fix

No patch or advisory is linked yet. Look at mitigations or restrict exposure.

Timeline

1. 2026-05-26 17:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-07-24 11:10 UTC Last updatedMost recent change to the record

Details

Published

2026-05-26 17:16 UTC

Last modified

2026-07-24 11:10 UTC

Exploit probability

0.1% · EPSS, next 30 days

Weakness

CWE-122

Record status

Analyzed

Affected

• pavel-odintsov Fastnetmon ≤ 1.2.9

Attack profile CVSS 3.1 · 7.1

Attack vector

Local

Complexity

Low

Privileges needed

Low

User interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

None