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.
Published: 2026-06-02
Score: 5.9 Medium
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
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Remediation

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History

Thu, 04 Jun 2026 16:45:00 +0000

Type Values Removed Values Added
Title FastNetMon Community Edition IPv4 Parser Out‑Bounds Read Leading to Potential Information Disclosure

Thu, 04 Jun 2026 14:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-843 CWE-125
Metrics cvssV3_1

{'score': 5.9, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N'}


Wed, 03 Jun 2026 18:15:00 +0000

Type Values Removed Values Added
Title FastNetMon Community Edition IPv4 Parser Out‑Bounds Read Leading to Potential Information Disclosure

Wed, 03 Jun 2026 16:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-843
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Wed, 03 Jun 2026 12:45:00 +0000

Type Values Removed Values Added
First Time appeared Pavel-odintsov
Pavel-odintsov fastnetmon
Vendors & Products Pavel-odintsov
Pavel-odintsov fastnetmon

Wed, 03 Jun 2026 02:30:00 +0000

Type Values Removed Values Added
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.
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Pavel-odintsov Fastnetmon
cve-icon MITRE

Status: PUBLISHED

Assigner: mitre

Published:

Updated: 2026-06-04T13:21:59.532Z

Reserved: 2026-05-22T00:00:00.000Z

Link: CVE-2026-48682

cve-icon Vulnrichment

Updated: 2026-06-03T16:03:41.527Z

cve-icon NVD

Status : Deferred

Published: 2026-06-02T20:16:38.993

Modified: 2026-06-04T16:28:59.003

Link: CVE-2026-48682

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-06-04T16:30:06Z

Weaknesses