CVEvulnerability
CVE-2026-48691
9.8 CRITICAL
Official page ↗
- Status
- Modified
- Published
- 2026-05-26
- Last modified
- 2026-07-24
- Assigner
- [email protected]
- CVSS 3.1 ([email protected])
- 9.8 CRITICAL — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CVSS 3.1 (134c704f-9b21-4f2e-91b3-4a467353bcc0)
- 7.3 HIGH — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
- Weaknesses
- CWE-122, CWE-190
Description
FastNetMon Community Edition through 1.2.9 contains an integer overflow in the BGP AS_PATH attribute encoder. In src/bgp_protocol.hpp, the IPv4UnicastAnnounce::get_attributes() function computes attribute_length as 'sizeof(bgp_as_path_segment_element_t) + this->as_path_asns.size() * sizeof(uint32_t)' and stores it in a uint8_t field (line 600-605). Since uint8_t can only hold values 0-255, an AS_PATH containing more than 63 ASNs (2 + 64*4 = 258 > 255) causes silent truncation. The truncated length is used for buffer sizing, while the actual data written is the full untruncated amount, resulting in a heap buffer overflow. Similarly, the path_segment_length field at line 621 is also uint8_t, truncating with more than 255 ASNs.
Affected configurations
• pavel-odintsov fastnetmon (<= 1.2.9)