Nessus vs OpenVAS usually gets framed as paid versus free. Three other questions matter more: what each scanner’s feed covers, what the licence allows, and who acts on the findings. This page compares the two on feeds, licensing limits, cost and operating work, with a dated source for every vendor fact. SITEY publishes this page. We connect to both scanners and sell neither, so SITEY comes in only after the comparison is done.
Nessus vs OpenVAS at a glance
The table covers only what we could source. Where a cell says confirm with the vendor, we found no source we were willing to cite, so we left the cell open rather than guess.
| Nessus (Tenable) | OpenVAS (Greenbone) | |
|---|---|---|
| Vendor | Tenable | Greenbone |
| Editions covered | Nessus Professional and Nessus Expert | OPENVAS FREE, plus editions with the Greenbone Enterprise Feed |
| Published price | Pro USD 4,790, Expert USD 6,790 for one year (see the tax note) | OPENVAS FREE edition; Enterprise Feed pricing not verified here |
| Intended use | Commercial licence; read Tenable’s terms for scope | OPENVAS FREE: “private use and non-professional IT infrastructures” |
| Checks for Cisco, MS Exchange, Palo Alto | Confirm with the vendor | Enterprise Feed only; the Community Feed row says “No” |
| Schedules, notifications, Airgap support | Confirm with the vendor | Not included in OPENVAS FREE |
| Next step up | Tenable Security Center (on-prem, priced by IP, quote) and Tenable Patch Management | Greenbone editions with the Enterprise Feed; OPENVAS AI is listed by Greenbone as upcoming |
you want a commercially licensed scanner with a published list price and a path into Tenable’s platform products later.
you are scanning a lab with OPENVAS FREE, or you have confirmed that the Greenbone feed edition you license covers your products.
finding vulnerabilities is not your bottleneck and closing them is. See Nessus vs Qualys below.
Greenbone Community Feed vs Enterprise Feed
A scanner can only find what its detection content checks for. OPENVAS FREE uses the Greenbone Community Feed. In Greenbone’s own feed comparison, the row for vulnerabilities in enterprise products (examples given: Cisco, MS Exchange and Palo Alto) reads “No” for the Community Feed. The Enterprise Feed covers them.
A clean scan report is only clean against the checks its feed contains.
So if you run Cisco, Exchange or Palo Alto equipment and scan with the Community Feed, an empty result for those devices is not evidence that they are patched. For Nessus, check your product list against Tenable’s current documentation; we do not quote plugin counts we have not verified. Before comparing prices, list the ten products your business depends on most and confirm the feed you will license covers each one.
Licensing and usage limits
This part of the OpenVAS vs Nessus decision is easy to overlook. Greenbone designs OPENVAS FREE for “private use and non-professional IT infrastructures” and lists schedules, notifications and Airgap support as not included. On a company network the comparison is therefore rarely free against USD 4,790. “Designed for” describes Greenbone’s intended audience, so read Greenbone’s terms for the edition you plan to run; if your products need the Enterprise Feed checks, schedules or notifications, compare Nessus with a Greenbone edition that includes the Enterprise Feed.
Tenable lists Nessus Professional and Expert with one-year prices. Read its licence terms before planning one licence across several teams or sites. For on-prem management beyond a single scanner, Tenable offers Tenable Security Center, “licensed by annual subscription and priced by IP”, with perpetual licensing also available.
What Nessus and OpenVAS cost
On 24 September 2026, Tenable’s buy page listed Nessus Professional at USD 4,790 and Nessus Expert at USD 6,790 for one year. An independent pricing guide updated on 6 April 2026 gives the same figures and says each is USD 400 above the previous price. Tenable Security Center has no online price; the buy page asks you to request a customized quote.
In some regions Tenable’s page shows prices with VAT included, so check the price and tax for your country. Prices change; treat these figures as a snapshot from 24 September 2026.
We have not verified list prices for Greenbone editions with the Enterprise Feed, so we give no figure; ask Greenbone for current pricing. An honest cost comparison has three lines: the scanner licence, the feed your product mix requires, and the staff time to run the scanner and act on its findings. That third line appears on no price list, and picking the cheaper scanner does not make it smaller.
Setup and operating burden
Neither scanner removes the recurring work: keeping detection content current, maintaining scan credentials, agreeing scan windows with system owners and routing results to the people who fix them. OPENVAS FREE has no schedules or notifications, so someone starts each scan and checks results by hand. Test these points before you commit.
- Your products against the feed
Confirm the feed you would license has checks for the products that matter most.
- Authenticated scans on known hosts
Scan one Windows and one Linux server whose software you know, and compare the output with what is really installed.
- Scheduling and alerting
Confirm the edition you would buy can scan on a schedule and notify someone. OPENVAS FREE cannot.
- The hand-off
Give a report to a system owner. If their answer is to research each item by hand, budget for that time.
Nessus vs Qualys: a scanner versus a platform
Nessus vs Qualys usually compares two different layers. Nessus Professional and Expert are scanners. Qualys VMDR is a platform: its AWS Marketplace listing (US only) offers it as SaaS in host-count packages, and Qualys also offers a Private Cloud Platform that runs “on your own premises”. Qualys Patch Management can remediate Windows assets with jobs combining missing patches and configuration scripts, through the Qualys Cloud Agent. A Qualys blog post from 17 September 2026 describes an autonomous remediation loop that validates exploitability, rolls patches out in waves and validates again, with humans setting the rules and thresholds and reviewing exceptions.
A closer comparison is Qualys VMDR against Tenable’s platform products, not Nessus alone: for an on-prem setup, for example, Tenable Security Center plus Tenable Patch Management, which runs on-premises or as SaaS and covers Windows (including drivers and BIOS), Mac, Linux and more than 20,000 third-party applications, with policies controlling how much runs autonomously. Decide first whether you want one vendor for scanning and fixing, or a scanner you keep plus a separate remediation layer.
Connect either scanner, or both, to SITEY
The scanner report is where remediation work starts. SITEY sits after it: it launches Nessus and OpenVAS scans directly and imports their results, along with results from 14 other scanners. You can connect both, so the choice above need not be permanent. Setup is covered on the Nessus integration and OpenVAS integration pages, and the full list is on scanner integrations.
AI triage estimates each finding’s false-positive probability and priority score from CVSS, EPSS and CISA KEV, stores its reasoning, and lets an analyst overrule it. AI remediation writes a bash or PowerShell script for the specific host. An approval gate with 4 autonomy levels and 18 risk-classified AI actions holds high-impact changes for a person. The SITEY agent then runs the approved script on the Windows or Linux endpoint, and a retest confirms closure. For OpenVAS findings, retest currently checks the whole rescan of that target, not the individual finding.
If AI processing must stay inside your network, note that Greenbone describes OPENVAS AI, listed as upcoming, as using a built-in on-premise LLM to produce remediation recommendations and automatable tasks. With SITEY, finding text and host context go to the AI endpoint you configure; you can pick one you host yourself or switch AI off.
SITEY costs USD 599 per month (cancellable) or USD 5,999 for a lifetime licence including one year of updates and the engine feed. The price is fixed, with no per-asset fee and no scan quota; each licence has an IP quota, see the pricing page. You buy online and install it yourself, and it comes on top of your scanner licence, not instead of it.
SITEY is not SaaS. It installs on your own Linux server (Ubuntu 22.04 or 24.04, Debian 12, RHEL or Rocky 9) with your own PostgreSQL database, and needs a technical person to install and run it. It is not air-gapped: it connects to siteyvm.com for licence activation and validation and for the engine feed. AI features use an OpenAI-compatible endpoint you choose, with your own key and at your own cost; AI usage is not included in the price. Each licence has an IP quota. And SITEY does not replace your scanner’s feed. Data handling is on the security page.
Frequently asked questions
Is OpenVAS free for business use?
Greenbone designs OPENVAS FREE for “private use and non-professional IT infrastructures”. It runs on the Community Feed and leaves out schedules, notifications and Airgap support. For a company network, look at the Greenbone editions that include the Enterprise Feed and read their licence terms.
What is the difference between the Greenbone Community Feed and the Enterprise Feed?
Greenbone’s feed comparison marks vulnerabilities in enterprise products, such as Cisco, MS Exchange and Palo Alto, as “No” for the Community Feed. The Enterprise Feed includes those checks. If you run those products, the Community Feed alone can leave them unchecked.
How much does Nessus cost?
On 24 September 2026, Tenable’s buy page listed Nessus Professional at USD 4,790 and Nessus Expert at USD 6,790 for one year. In some regions the page shows prices with VAT included, so confirm the price and tax for your country.
Can I run Nessus and OpenVAS together?
Yes. SITEY launches scans on both and imports their results into one queue, where every finding goes through the same triage, remediation and retest steps. One limitation: an OpenVAS retest currently checks the whole rescan of that target, not the individual finding.
Does SITEY work air-gapped, and what data leaves the network?
No, SITEY is not air-gapped. It connects to siteyvm.com for licence activation and validation and for the engine feed. Neither connection carries scan data. If you turn on AI, finding text and host context go to the OpenAI-compatible endpoint you choose, using your own key. That can be an endpoint you host yourself, or you can switch AI off. Optional lookups go to NVD, CISA KEV, FIRST EPSS, MSRC and the Microsoft Update Catalog.
Does SITEY replace Nessus or OpenVAS?
No. What gets detected still depends on your scanner and its feed. SITEY takes over from the report onwards: triage, the fix, approval and retest.
Sources
- Tenable, Buy page: Nessus Professional and Expert prices; Security Center by quote. https://www.tenable.com/buy, accessed 24 September 2026.
- Valydex, Tenable Nessus pricing guide, updated 6 April 2026. https://valydex.com/guides/tenable-nessus-pricing, accessed 24 September 2026.
- Tenable, Tenable Security Center: on-prem, priced by IP, perpetual option. https://www.tenable.com/products/security-center, accessed 24 September 2026.
- Tenable, Tenable Patch Management: deployment options and coverage. https://www.tenable.com/products/patch-management, accessed 24 September 2026.
- Greenbone, OPENVAS FREE: intended use, Community Feed, excluded features. https://www.greenbone.net/en/openvas-free/, accessed 24 September 2026.
- Greenbone, Feed comparison: Community Feed vs Enterprise Feed. https://www.greenbone.net/en/feed-comparison/, accessed 24 September 2026.
- Greenbone, OPENVAS AI (Upcoming Solutions). https://www.greenbone.net/en/openvas-ai/, accessed 24 September 2026.
- AWS Marketplace, Qualys VMDR (US Only) listing. https://aws.amazon.com/marketplace/pp/prodview-5g6ecotizcru6, accessed 24 September 2026.
- Qualys, Private Cloud Platform. https://www.qualys.com/private-cloud, accessed 24 September 2026.
- Qualys documentation, Patch Management remediation with configuration scripts. https://docs.qualys.com/en/pm/latest/patches/vuln_remediation_config_scripts.htm, accessed 24 September 2026.
- Qualys blog, 17 September 2026, autonomous remediation. https://blog.qualys.com/product-tech/2026/09/17/the-autonomous-engine-behind-remediation-and-what-finally-makes-it-safe, accessed 24 September 2026.
Nessus and Tenable are trademarks of Tenable, Inc. OpenVAS and Greenbone are trademarks of Greenbone AG. Qualys is a trademark of Qualys, Inc. SITEY is not affiliated with or endorsed by Tenable, Greenbone or Qualys.