DEBIAN-CVE-2026-48686
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.
DEBIAN-CVE-2026-48686
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-2026-48686
fastnetmon
Source reference: /affected/0/package/name
- Affected versions
- 1.2.4-2
Source reference:
/affected/0/versions1.2.4-2+deb12u1Source reference:
/affected/0/versions1.2.5-1Source reference:
/affected/0/versions1.2.5-2Source reference:
/affected/0/versions1.2.5-2~bpo12+1Source reference:
/affected/0/versions1.2.6-1Source reference:
/affected/0/versions1.2.6-1~bpo12+1Source reference:
/affected/0/versions1.2.7-1Source reference:
/affected/0/versions1.2.7-1~bpo12+1Source reference:
/affected/0/versions1.2.8+git20250911-1Source reference:
/affected/0/versions1.2.8+git20250911-2Source reference:
/affected/0/versions1.2.8-1Source reference:
/affected/0/versions1.2.8-1~bpo12+1Source reference:
/affected/0/versions1.2.9-1Source reference:
/affected/0/versions - Fixed versions
- Not stated in this record
- 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
- 1.2.9-0+deb13u1
Source reference:
/affected/1/ranges - Prerequisites
- Not stated in this record
fastnetmon
Source reference: /affected/2/package/name
- Affected versions
- 1.2.8+git20250911-1
Source reference:
/affected/2/versions1.2.8+git20250911-2Source reference:
/affected/2/versions1.2.8-1Source reference:
/affected/2/versions - Fixed versions
- 1.2.9-1
Source reference:
/affected/2/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"
}
]
}
],
"package": {
"name": "fastnetmon",
"purl": "pkg:deb/debian/fastnetmon?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
},
"versions": [
"1.2.4-2",
"1.2.4-2+deb12u1",
"1.2.5-1",
"1.2.5-2",
"1.2.5-2~bpo12+1",
"1.2.6-1",
"1.2.6-1~bpo12+1",
"1.2.7-1",
"1.2.7-1~bpo12+1",
"1.2.8+git20250911-1",
"1.2.8+git20250911-2",
"1.2.8-1",
"1.2.8-1~bpo12+1",
"1.2.9-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-48686.json"
},
"ecosystem_specific": {
"urgency": "unimportant"
}
},
{
"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-2026-48686.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-2026-48686.json"
},
"ecosystem_specific": {
"urgency": "unimportant"
}
}
]Publisher severity
No explicit severity was provided.
- Event
- #57231 · Revision 1
- Added to Heist Feed
- Publisher date