Track vulnerabilities like this one. Sign up free to get alerted when software you use is affected.

CVE-2026-48683: FastNetMon Community Edition allows reading arbitrary memory

CVE-2026-48683 · published 5 months ago

Summary

FastNetMon Community Edition, a network monitoring tool, contains a vulnerability that allows an attacker to read sensitive information from memory. This can happen when an attacker sends malicious data to the tool, which can then cause a crash or reveal confidential information. To protect yourself, update to the latest version of FastNetMon Community Edition.

What to do

Update debian fastnetmon to version 1.2.9-1.

Affected software

Ecosystem	Vendor	Product	Affected versions
Debian:12	debian	fastnetmon	All versions
Debian:13	debian	fastnetmon	All versions
Debian:14	debian	fastnetmon	< 1.2.9-1 Fix: upgrade to 1.2.9-1
Ubuntu:18.04:LTS	canonical	fastnetmon	All versions

Original advisory text

FastNetMon Community Edition through 1.2.9 contains an out-of-bounds read vulnerability in the NetFlow v9 data flowset processor. In src/netflow_plugin/netflow_v9_collector.cpp, the Data template branch (lines 1695-1702) iterates over flow records without performing a per-iteration bounds check against the packet end pointer. In contrast, the Options template branch (lines 1709-1719) correctly checks 'if (pkt + offset + field_template->total_length > packet_end)' before each iteration. The Data branch omits this check entirely. Since template definitions are sent by the network peer (and are unauthenticated UDP), an attacker can craft templates that cause the parser to read arbitrary memory past the packet buffer. This can leak sensitive memory contents or cause a crash.

References

https://lorikeetsecurity.com/blog/fastnetmon-cve-2026-48683-netflow-v9-data-oob Third Party Advisory
https://github.com/pavel-odintsov/fastnetmon Third Party Advisory
https://security-tracker.debian.org/tracker/CVE-2026-48683 Vendor Advisory
https://ubuntu.com/security/CVE-2026-48683 Third Party Advisory
https://www.cve.org/CVERecord?id=CVE-2026-48683 Third Party Advisory
https://github.com/pavel-odintsov/fastnetmon/commit/aa1069abaa8624e50b5d0c6c8ccd... Third Party Advisory
https://github.com/pavel-odintsov/fastnetmon/pull/1057 Third Party Advisory
https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/48xxx/CVE-2026-48683... Vendor Advisory
https://nvd.nist.gov/vuln/detail/CVE-2026-48683 Vendor Advisory
https://github.com/pavel-odintsov/fastnetmon/blob/master/src/netflow_plugin/netf... Third Party Advisory

Fix within

Internet-facing 60 days

Internal At next upgrade

Not known to be exploited
Needs hands-on effort to exploit
Gives an attacker partial control

Severity

6.5 Medium

Exploitation

<1% chance of attack within 30 days

Type

CWE-125Out-of-bounds Read

Timeline

Published26 May 2026

Updated4 Nov 2026

First seen26 May 2026

Sources

CVE-2026-48683 · NVD

DEBIAN-CVE-2026-48683 · OSV

UBUNTU-CVE-2026-48683 · OSV

CVE-2026-48683 · OSV

Track software like this

Free during beta