FastNetMon: Legacy pcap parse_packet() has no bounds checking, causing out-of-bounds read on truncated frames
Only FastNetMon 1.2.9 and earlier, when legacy pcap capture mode is enabled (pcap = on), is in scope. CVSS rates it 8.2 (high). The checked facts list no fixed release.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
- Exploited
- No known exploitation
- Fix
- No fix listed
- Who is exposed
- Not reported
Do first: Workaround: The checked facts list no fix. Limiting exposure means disabling pcap capture mode (pcap = on) where the deployment does not need it, since the flaw sits in the pcap callback path.
- Last modified
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 30/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Unclear
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
FastNetMon, a DDoS detector and sensor, can be crashed through a flaw in its legacy pcap packet parser, which fails to check captured frame lengths. A remote attacker can trigger an out-of-bounds read that terminates the process, and this can be done over the network without logging in; the bug affects version 1.2.9 and earlier, and no fixed release is available yet.
Read the original description
FastNetMon is a high-performance DDoS detector and sensor. In version 1.2.9 and earlier, the live parse_packet() callback in src/pcap_plugin/pcap_collector.cpp is registered through pcap_loop and processes captured frames when pcap = on without checking packethdr->caplen. A short frame or an attacker-controlled IPv4 header length can make the parser dereference IP or transport headers beyond the captured bytes, causing an out-of-bounds read and process termination. No fixed release is available as of this review.
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure17/25No login or user action needed, reachable over the network without a login · Unknown: Advisories don't say whether default setups are affected
- Reach?/20Unknown. No tracked technology or package matched
- Severity8.2/10CVSS 8.2
- No patch5/5No patch listed yet
What would change the score
- Would score about 75 if added to CISA KEV
- Would score about 70 if CISA's SSVC rates exploitation active
- Would score about 35 if advisories confirm default setups are exposed
What to do
Workaround: The checked facts list no fix. Limiting exposure means disabling pcap capture mode (pcap = on) where the deployment does not need it, since the flaw sits in the pcap callback path.
Timeline
- CVE published
- First seen by cve.now
Affected versions
- pavel-odintsov fastnetmon
through 1.2.9
Evidence 2
- Advisory
- Repository
Corrections
None so far.
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Questions about CVE-2026-92695
Is CVE-2026-92695 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
What does this mean?
The legacy pcap parse_packet() function does not check bounds, so a short or truncated captured frame makes it read past the end of its data. This out-of-bounds read crashes the FastNetMon process.Source: github.com
Which versions are affected by CVE-2026-92695?
fastnetmon: through 1.2.9.Source: cve.now feed data
Am I affected, and how do I check?
Versions up to and including 1.2.9 are in scope, but only when pcap capture mode is enabled (pcap = on). To check, look for the pcap setting in the FastNetMon configuration file and confirm the installed version.Source: github.com
How do I fix CVE-2026-92695?
The checked facts do not name a fixed version, so no upgrade target can be given. Check the vendor's advisory for a release that addresses this issue.Source: github.com
What if there's no patch?
The checked facts list no fix. Limiting exposure means disabling pcap capture mode (pcap = on) where the deployment does not need it, since the flaw sits in the pcap callback path.Source: github.com