DEBIAN-CVE-2026-48689
FastNetMon Community Edition through 1.2.9 contains an off-by-one heap-based buffer overflow in the dynamic_binary_buffer_t class (src/dynamic_binary_buffer.hpp). Five methods (append_dynamic_buffer, append_data_as_pointer, append_data_as_object_ptr, memcpy_from_ptr, memcpy_from_object_ptr) use an incorrect bounds check of the form 'if (offset + length > maximum_internal_storage_size + 1)' instead of the correct 'if (offset + length > maximum_internal_storage_size)'. This allows writing exactly one byte past the end of the heap-allocated buffer. The class is used pervasively in BGP message encoding/decoding, NetFlow template processing, and Flow Spec NLRI construction. An attacker who can send network traffic (NetFlow, sFlow, IPFIX, or BGP) to a FastNetMon instance can trigger this overflow, potentially achieving arbitrary code execution by corrupting heap metadata. Notably, the append_byte() method uses the correct bounds check, confirming the inconsistency.
DEBIAN-CVE-2026-48689
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: osv:DEBIAN-CVE-2026-48689
fastnetmon
Source reference: /affected/0/package/name
- Affected versions
- 1.2.8+git20250911-1
Source reference:
/affected/0/versions1.2.8+git20250911-2Source reference:
/affected/0/versions1.2.8-1Source reference:
/affected/0/versions - Fixed versions
- 1.2.9-0+deb13u1
Source reference:
/affected/0/ranges - Prerequisites
- Not stated in this record
fastnetmon
Source reference: /affected/1/package/name
- Affected versions
- 1.2.8+git20250911-1
Source reference:
/affected/1/versions1.2.8+git20250911-2Source reference:
/affected/1/versions1.2.8-1Source reference:
/affected/1/versions - Fixed versions
- 1.2.9-1
Source reference:
/affected/1/ranges - Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "1.2.9-0+deb13u1"
}
]
}
],
"package": {
"name": "fastnetmon",
"purl": "pkg:deb/debian/fastnetmon?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"versions": [
"1.2.8+git20250911-1",
"1.2.8+git20250911-2",
"1.2.8-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-48689.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "1.2.9-1"
}
]
}
],
"package": {
"name": "fastnetmon",
"purl": "pkg:deb/debian/fastnetmon?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"versions": [
"1.2.8+git20250911-1",
"1.2.8+git20250911-2",
"1.2.8-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-48689.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
]Publisher severity
No explicit severity was provided.
- Event
- #57221 · Revision 1
- Added to Heist Feed
- Publisher date