{"dataType": "CVE_RECORD", "cveMetadata": {"state": "PUBLISHED", "cveId": "CVE-2026-48686", "assignerOrgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca", "assignerShortName": "mitre", "dateUpdated": "2026-05-26T14:46:38.784Z", "dateReserved": "2026-05-22T00:00:00.000Z", "datePublished": "2026-05-26T00:00:00.000Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca", "shortName": "mitre", "dateUpdated": "2026-05-26T14:46:38.784Z"}, "descriptions": [{"lang": "en", "value": "FastNetMon Community Edition through 1.2.9 contains a stack-based buffer overflow in the BGP NLRI (Network Layer Reachability Information) decoder. The function decode_bgp_subnet_encoding_ipv4_raw() in src/bgp_protocol.cpp reads prefix_bit_length directly from the BGP packet (line 99) without validating it is <= 32 for IPv4 prefixes. This value is passed to how_much_bytes_we_need_for_storing_certain_subnet_mask() which computes ceil(prefix_bit_length / 8), returning up to 32 bytes for a prefix_bit_length of 255. The result is used as the length argument to memcpy() (line 106), which copies into a 4-byte uint32_t stack variable (prefix_ipv4). This causes a stack buffer overflow of up to 28 bytes, which can be exploited for arbitrary code execution. Additionally, the unvalidated prefix_bit_length is passed to convert_cidr_to_binary_netmask_local_function_copy() (line 111), where a shift of (32 - cidr) with cidr > 32 causes undefined behavior."}], "affected": [{"vendor": "n/a", "product": "n/a", "versions": [{"version": "n/a", "status": "affected"}]}], "references": [{"url": "https://github.com/pavel-odintsov/fastnetmon"}, {"url": "https://github.com/pavel-odintsov/fastnetmon/blob/master/src/bgp_protocol.cpp"}, {"url": "https://lorikeetsecurity.com/blog/fastnetmon-cve-2026-48686-bgp-nlri-stack-overflow"}], "problemTypes": [{"descriptions": [{"type": "text", "lang": "en", "description": "n/a"}]}]}}, "dataVersion": "5.2"}

{}

{"cveTags": [], "descriptions": [{"lang": "en", "value": "FastNetMon Community Edition through 1.2.9 contains a stack-based buffer overflow in the BGP NLRI (Network Layer Reachability Information) decoder. The function decode_bgp_subnet_encoding_ipv4_raw() in src/bgp_protocol.cpp reads prefix_bit_length directly from the BGP packet (line 99) without validating it is <= 32 for IPv4 prefixes. This value is passed to how_much_bytes_we_need_for_storing_certain_subnet_mask() which computes ceil(prefix_bit_length / 8), returning up to 32 bytes for a prefix_bit_length of 255. The result is used as the length argument to memcpy() (line 106), which copies into a 4-byte uint32_t stack variable (prefix_ipv4). This causes a stack buffer overflow of up to 28 bytes, which can be exploited for arbitrary code execution. Additionally, the unvalidated prefix_bit_length is passed to convert_cidr_to_binary_netmask_local_function_copy() (line 111), where a shift of (32 - cidr) with cidr > 32 causes undefined behavior."}], "id": "CVE-2026-48686", "lastModified": "2026-05-26T16:16:26.693", "metrics": {}, "published": "2026-05-26T16:16:26.693", "references": [{"source": "cve@mitre.org", "url": "https://github.com/pavel-odintsov/fastnetmon"}, {"source": "cve@mitre.org", "url": "https://github.com/pavel-odintsov/fastnetmon/blob/master/src/bgp_protocol.cpp"}, {"source": "cve@mitre.org", "url": "https://lorikeetsecurity.com/blog/fastnetmon-cve-2026-48686-bgp-nlri-stack-overflow"}], "sourceIdentifier": "cve@mitre.org", "vulnStatus": "Received"}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[0,1.2.9]"}}], "enrichment": {"confidence": 85.0, "confidence_source": "inferred", "scores": [{"score": 85.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "n/a", "source": "cna", "vendor": "n/a"}, "product": "fastnetmon", "vendor": "pavel-odintsov"}], "created": "2026-05-26T16:30:09.738603+00:00", "title": "Stack Corruption in FastNetMon BGP NLRI Decoder Leading to Arbitrary Code Execution", "updated": "2026-05-26T16:30:10.047938+00:00", "vendors": ["pavel-odintsov", "pavel-odintsov$PRODUCT$fastnetmon"], "weaknesses": ["CWE-120"]}