CVE-2026-48688
Out-of-Bounds Reads in FastNetMon Community Edition
Publication date: 2026-05-26
Last updated on: 2026-05-26
Assigner: MITRE
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| fastnetmon | community_edition | to 1.2.9 (inc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-UNKNOWN |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
CVE-2026-48688 is a vulnerability in FastNetMon Community Edition through version 1.2.9 involving multiple out-of-bounds reads in the BGP MP_REACH_NLRI IPv6 attribute decoder.
Specifically, the function decode_mp_reach_ipv6() in the source code lacks proper sanity checks and bounds validation when processing certain IPv6 attributes. It casts raw pointers to structure types without verifying sufficient data exists, uses an attacker-controlled length field to determine memory copy sizes, and calculates prefix lengths from attacker-controlled offsets without validating buffer boundaries.
These flaws can lead to reading memory beyond the intended buffer limits, which is unsafe and can cause crashes or potentially expose sensitive data.
How can this vulnerability impact me? :
This vulnerability can lead to out-of-bounds memory reads when processing BGP IPv6 attributes, which may cause application crashes or undefined behavior.
An attacker could exploit this flaw by sending specially crafted BGP messages that trigger these out-of-bounds reads, potentially leading to denial of service or exposure of sensitive memory contents.
How can this vulnerability be detected on my network or system? Can you suggest some commands?
The vulnerability involves improper handling of BGP MP_REACH_NLRI IPv6 attributes, specifically out-of-bounds reads caused by malformed BGP UPDATE messages. Detection can focus on monitoring and analyzing BGP traffic for malformed or suspicious MP_REACH_NLRI IPv6 attributes.
Commands to detect this vulnerability could include capturing and inspecting BGP UPDATE messages on your network using packet capture tools such as tcpdump or Wireshark, filtering for BGP traffic and specifically examining the MP_REACH_NLRI IPv6 attributes for anomalies.
- Use tcpdump to capture BGP traffic: tcpdump -i <interface> port 179 -w bgp_traffic.pcap
- Analyze the capture with Wireshark, filtering for BGP UPDATE messages and inspecting MP_REACH_NLRI IPv6 attributes for malformed data.
- Use custom scripts or tools to parse BGP UPDATE messages and validate the length fields and prefix lengths in MP_REACH_NLRI IPv6 attributes to detect out-of-bounds or suspicious values.
What immediate steps should I take to mitigate this vulnerability?
Immediate mitigation steps include updating FastNetMon Community Edition to a version that addresses this vulnerability once available.
Until a patch is released, consider restricting or filtering BGP UPDATE messages from untrusted sources to prevent maliciously crafted MP_REACH_NLRI IPv6 attributes from reaching the vulnerable code.
Implement network-level controls such as prefix filtering, maximum prefix limits, and strict validation of BGP attributes on your routers or BGP peers to reduce exposure.
Monitor logs and alerts for unusual BGP activity or crashes related to BGP processing in FastNetMon.