FastNetMon: NetFlow v9 unbounded strlen() on interface-description field causes remote out-of-bounds read
Affects FastNetMon 1.2.9 and earlier when the NetFlow v9 collector processes options templates with an interface-description field. No fix is listed yet.
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 facts list no fix and no workaround. The affected feature is the NetFlow v9 collector receiving UDP packets, so limiting or disabling that collector is the only step the facts point to until a fix is released.
- 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 detection and sensor product, contains a flaw in its NetFlow v9 collector that lets an attacker remotely, without logging in, send crafted UDP packets that cause an out-of-bounds read, which can crash the process and cause a denial of service. 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 NetFlow v9 collector calls strlen() on an attacker-controlled interface-description field without bounding the scan to the field’s declared length. Although fields longer than 128 bytes are excluded from this operation, an accepted field without a null terminator can cause reads beyond the field and packet buffer. An unauthenticated remote attacker who can send crafted UDP packets to the collector can trigger an out-of-bounds read and potentially crash the process, causing denial of service. 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
- Severity7.5/10CVSS 7.5
- 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 facts list no fix and no workaround. The affected feature is the NetFlow v9 collector receiving UDP packets, so limiting or disabling that collector is the only step the facts point to until a fix is released.
Timeline
- CVE published
- First seen by cve.now
Affected versions
- pavel-odintsov fastnetmon
through 1.2.9
Evidence 3
- Advisory
- Repository
- Repository
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-92697
Is CVE-2026-92697 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 NetFlow v9 collector calls strlen() on bytes from UDP packets without a length limit, so a crafted packet can crash the collector process. The attack needs no login.Source: github.com
Which versions are affected by CVE-2026-92697?
fastnetmon: through 1.2.9.Source: cve.now feed data
Am I affected, and how do I check?
FastNetMon versions up to and including 1.2.9 are listed as affected. The bug applies when the NetFlow v9 collector receives UDP packets and processes an options template with the interface-description field (type 83). To check, look at the installed FastNetMon version and whether the NetFlow v9 collector is enabled.Source: github.com
How do I fix CVE-2026-92697?
The facts list no fixed version, so no specific upgrade target is known. Check the vendor for a release newer than 1.2.9 and install it when it is available.Source: github.com
What if there's no patch?
The facts list no fix and no workaround. The affected feature is the NetFlow v9 collector receiving UDP packets, so limiting or disabling that collector is the only step the facts point to until a fix is released.Source: github.com