# CVE-2026-48688: FastNetMon Community Edition out-of-bounds reads in BGP decoder

Source: https://junglewise.ai/threats/cve-2026-48688-fastnetmon-community-edition-out-of-bounds-reads-in-bgp-decoder  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-05-26. Updated: 2026-05-26  
License: CC BY 4.0 with a link back

CVE-2026-48688 · Severity: info · CVSS 7.5 · Published 2026-05-26

FastNetMon Community Edition, a tool used for monitoring network traffic and detecting DDoS attacks, contains a security flaw in how it processes BGP (Border Gateway Protocol) messages. An attacker can send specially crafted network routing updates that cause the software to read beyond its intended memory boundaries. This could allow an attacker to crash the service or potentially access sensitive information from the system's memory, such as routing tables or peer data.

## Quick answers

**Is CVE-2026-48688 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-48688 being exploited in the wild.

**How severe is CVE-2026-48688?** Informational severity, with a CVSS score of 7.5, published 26 May 2026.

**Which products and versions are affected?** FastNetMon FastNetMon Community Edition through 1.2.9.

**Is there a fix for CVE-2026-48688?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-48688 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-48688?** Check whether anything you run is named in the advisory. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability exists in the decode_mp_reach_ipv6() function within src/bgp_protocol.cpp. The parser fails to validate the length of BGP attributes before performing pointer arithmetic and memory copies. Specifically, it casts raw pointers to structure types without size verification, uses attacker-controlled 'length_of_next_hop' fields to determine memcpy sizes, and calculates prefix lengths using unvalidated offsets. A remote attacker can exploit this by sending malformed BGP MP_REACH_NLRI attributes, leading to out-of-bounds reads. This can result in a denial-of-service (crash) or the disclosure of sensitive heap/stack memory, such as route table entries or peer state. As of the advisory date, no official patch has been released.

## Affected products

- FastNetMon FastNetMon Community Edition through 1.2.9

## Timeline

- 2026-04-25: other: Lorikeet Security notified FastNetMon LTD
- 2026-05-23: advisory: Public disclosure by Lorikeet Security
- 2026-05-26: disclosed: CVE-2026-48688 published to NVD

## References

- [https://github.com/pavel-odintsov/fastnetmon](https://github.com/pavel-odintsov/fastnetmon)
- [https://github.com/pavel-odintsov/fastnetmon/blob/master/src/bgp_protocol.cpp](https://github.com/pavel-odintsov/fastnetmon/blob/master/src/bgp_protocol.cpp)
- [https://lorikeetsecurity.com/blog/fastnetmon-cve-2026-48688-bgp-mp-reach-nlri-ipv6](https://lorikeetsecurity.com/blog/fastnetmon-cve-2026-48688-bgp-mp-reach-nlri-ipv6)