CVE-2026-48685
Out-of-Bounds Memory Access 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
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
The provided information does not specify any direct impact of CVE-2026-48685 on compliance with common standards and regulations such as GDPR or HIPAA.
Can you explain this vulnerability to me?
CVE-2026-48685 is a vulnerability in FastNetMon Community Edition versions 1.2.9 and earlier where the BGP attribute parser incorrectly handles extended-length attributes.
The issue occurs in the parse_raw_bgp_attribute() function in src/bgp_protocol.hpp. When processing BGP attributes with the Extended Length flag set, which indicates a two-byte length field, the parser only reads one byte instead of two. This causes the parser to misinterpret attribute lengths, truncating the length to the low byte and treating the remaining bytes as part of subsequent attributes or phantom attributes.
This parsing error leads to cascading parse failures and potential out-of-bounds memory access, which can cause type confusion, length-field underflows, and incorrect routing decisions.
How can this vulnerability impact me? :
This vulnerability can impact you by causing the FastNetMon software to misinterpret BGP path attributes, leading to cascading parse failures and out-of-bounds memory access.
Such memory access issues can result in type confusion and length-field underflows, potentially destabilizing the application or causing incorrect routing decisions.
Because the vulnerability requires a trusted BGP peer and the presence of an external GoBGP daemon acting as a prefilter, exploitation is somewhat constrained, but still poses a medium risk (CVSS score 6.5).
How can this vulnerability be detected on my network or system? Can you suggest some commands?
This vulnerability can be detected by monitoring for parse errors related to BGP attributes with the extended length flag set. Since the parser misinterprets attribute lengths, observing unusual or cascading parse failures in BGP messages is a key indicator.
Additionally, constraining and filtering BGP peers and attributes at the external speaker can help identify suspicious or malformed BGP attributes that trigger this issue.
While no specific commands are provided in the resources, typical detection commands might include inspecting BGP logs for parse errors or using packet capture tools (e.g., tcpdump or Wireshark) to analyze BGP update messages for attributes with extended length flags and verifying their length fields.
What immediate steps should I take to mitigate this vulnerability?
Immediate mitigation steps include constraining BGP peers to trusted sources and filtering BGP attributes at the external speaker to prevent malformed or overly long attributes from reaching the vulnerable parser.
Capping attribute lengths to acceptable limits can reduce the risk of triggering the out-of-bounds memory access.
Monitoring parse errors closely can help detect exploitation attempts early.
As of the latest information, no vendor fix is available, so these network-level mitigations are critical.