CVE-2026-48682: n/a
FastNetMon Community Edition through 1.2.9 contains an out-of-bounds read in the IPv4 packet parser. In src/simple_packet_parser_ng.cpp, after validating that the packet contains at least sizeof(ipv4_header_t) bytes (20 bytes), the code advances the local_pointer by '4 * ipv4_header->get_ihl()' (line 164) without validating that (a) IHL >= 5 (the minimum valid value per RFC 791), or (b) 4 * IHL bytes are actually available in the packet. The IHL field is 4 bits, allowing values 0-15, so the advance can be 0-60 bytes. An IHL value of 15 with only 20 bytes validated causes a 40-byte over-read. An IHL of 0-4 causes the pointer to not advance past the IP header, resulting in the TCP/UDP header being parsed from IP header data (type confusion). This vulnerability is reachable via any packet capture interface.
AI Analysis
Technical Summary
The vulnerability in FastNetMon Community Edition (≤1.2.9) is due to improper validation of the IPv4 header length (IHL) field in the packet parser. After confirming the packet has at least 20 bytes, the code advances a pointer by '4 * IHL' bytes without ensuring IHL is at least 5 or that the packet contains sufficient bytes for this advance. Since IHL is a 4-bit field (0-15), values less than 5 cause the pointer to not move past the IP header, leading to type confusion when parsing TCP/UDP headers. Values greater than 5 but with insufficient packet length cause out-of-bounds reads. This vulnerability can be triggered by any packet capture interface, potentially leading to memory safety issues.
Potential Impact
This vulnerability can lead to out-of-bounds memory reads or type confusion during packet parsing, which may cause application crashes or undefined behavior. The exact impact depends on how the application handles such memory errors. There is no evidence of exploitation in the wild or further impact such as code execution disclosed.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, users should consider limiting exposure of FastNetMon to untrusted packet sources or interfaces. Monitor vendor channels for updates and apply patches promptly once released.
CVE-2026-48682: n/a
Description
FastNetMon Community Edition through 1.2.9 contains an out-of-bounds read in the IPv4 packet parser. In src/simple_packet_parser_ng.cpp, after validating that the packet contains at least sizeof(ipv4_header_t) bytes (20 bytes), the code advances the local_pointer by '4 * ipv4_header->get_ihl()' (line 164) without validating that (a) IHL >= 5 (the minimum valid value per RFC 791), or (b) 4 * IHL bytes are actually available in the packet. The IHL field is 4 bits, allowing values 0-15, so the advance can be 0-60 bytes. An IHL value of 15 with only 20 bytes validated causes a 40-byte over-read. An IHL of 0-4 causes the pointer to not advance past the IP header, resulting in the TCP/UDP header being parsed from IP header data (type confusion). This vulnerability is reachable via any packet capture interface.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability in FastNetMon Community Edition (≤1.2.9) is due to improper validation of the IPv4 header length (IHL) field in the packet parser. After confirming the packet has at least 20 bytes, the code advances a pointer by '4 * IHL' bytes without ensuring IHL is at least 5 or that the packet contains sufficient bytes for this advance. Since IHL is a 4-bit field (0-15), values less than 5 cause the pointer to not move past the IP header, leading to type confusion when parsing TCP/UDP headers. Values greater than 5 but with insufficient packet length cause out-of-bounds reads. This vulnerability can be triggered by any packet capture interface, potentially leading to memory safety issues.
Potential Impact
This vulnerability can lead to out-of-bounds memory reads or type confusion during packet parsing, which may cause application crashes or undefined behavior. The exact impact depends on how the application handles such memory errors. There is no evidence of exploitation in the wild or further impact such as code execution disclosed.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, users should consider limiting exposure of FastNetMon to untrusted packet sources or interfaces. Monitor vendor channels for updates and apply patches promptly once released.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- mitre
- Date Reserved
- 2026-05-22T00:00:00.000Z
- Cvss Version
- null
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a1f3494e29bf47b50fa2549
Added to database: 6/2/2026, 7:52:52 PM
Last enriched: 6/2/2026, 8:04:08 PM
Last updated: 6/3/2026, 4:59:48 AM
Views: 7
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