DEBIAN-CVE-2026-48686
- Source
- https://security-tracker.debian.org/tracker/CVE-2026-48686
- Import Source
- https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-48686.json
- JSON Data
- https://api.osv.dev/v1/vulns/DEBIAN-CVE-2026-48686
- Upstream
- Published
- 2026-05-26T16:16:26Z
- Modified
- 2026-09-14T17:03:16Z
- Severity
-
- 9.8 (Critical) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H CVSS Calculator
- Summary
- [none]
- Details
-
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.
- References
Affected packages
Debian:12 / fastnetmon
Package
- Name
- fastnetmon
- Purl
- pkg:deb/debian/fastnetmon?arch=source&distro=bookworm
Affected ranges
- Type
- ECOSYSTEM
- Events
-
Introduced0 Unknown introduced version / All previous versions are affected
Debian:13 / fastnetmon
Package
- Name
- fastnetmon
- Purl
- pkg:deb/debian/fastnetmon?arch=source&distro=trixie
Debian:14 / fastnetmon
Package
- Name
- fastnetmon
- Purl
- pkg:deb/debian/fastnetmon?arch=source&distro=forky