CVE-2026-48686
FastNetMon Community Edition through 1.2.9 contains a stack-based buff ...
Severity by source
Trivy's own label is CRITICAL. Rated critical by NVD. Rated lower by Ubuntu (medium).
Description
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 packages and fixed versions
| Source | Package | Fixed in |
|---|---|---|
| debian 12 | fastnetmon | no fix listed |
| debian 13 | fastnetmon | 1.2.9-0+deb13u1 |
| debian 14 | fastnetmon | 1.2.9-1 |
| echo | fastnetmon | 1.2.9-0+deb13u1 |
| rapidfort debian 12 | fastnetmon | 0:1.2.9-0+deb13u1, 0:1.2.9-1 |
| rapidfort debian 13 | fastnetmon | 0:1.2.9-0+deb13u1, 0:1.2.9-1 |
| rapidfort fedora 43 | fastnetmon | 1.2.9-2.fc43 |
| rapidfort Oracle Linux 10 | fastnetmon | no fix listed |
| rapidfort Oracle Linux 9 | fastnetmon | no fix listed |
| rapidfort ubuntu 20.04 | fastnetmon | no fix listed |
| rapidfort ubuntu 22.04 | fastnetmon | no fix listed |
| rapidfort ubuntu 24.04 | fastnetmon | no fix listed |
Show all 14 entries from 14 sources
| Source | Package | Fixed in |
|---|---|---|
| debian 12 | fastnetmon | no fix listed |
| debian 13 | fastnetmon | 1.2.9-0+deb13u1 |
| debian 14 | fastnetmon | 1.2.9-1 |
| echo | fastnetmon | 1.2.9-0+deb13u1 |
| rapidfort debian 12 | fastnetmon | 0:1.2.9-0+deb13u1, 0:1.2.9-1 |
| rapidfort debian 13 | fastnetmon | 0:1.2.9-0+deb13u1, 0:1.2.9-1 |
| rapidfort fedora 43 | fastnetmon | 1.2.9-2.fc43 |
| rapidfort Oracle Linux 10 | fastnetmon | no fix listed |
| rapidfort Oracle Linux 9 | fastnetmon | no fix listed |
| rapidfort ubuntu 20.04 | fastnetmon | no fix listed |
| rapidfort ubuntu 22.04 | fastnetmon | no fix listed |
| rapidfort ubuntu 24.04 | fastnetmon | no fix listed |
| ubuntu 24.04 | fastnetmon | no fix listed |
| ubuntu 26.04 | fastnetmon | no fix listed |
References
- https://github.com/pavel-odintsov/fastnetmon
- https://github.com/pavel-odintsov/fastnetmon/blob/master/src/bgp_protocol.cpp
- https://github.com/pavel-odintsov/fastnetmon/commit/265a767635767d7a08391dbe7f98f750d2ea04d0
- https://github.com/pavel-odintsov/fastnetmon/pull/1053
- https://lorikeetsecurity.com/blog/fastnetmon-cve-2026-48686-bgp-nlri-stack-overflow
- https://ubuntu.com/security/notices/USN-8429-1
- https://www.cve.org/CVERecord?id=CVE-2026-48686