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Cybersecurity · head to head

Syft vs Tenable Nessus

Syft logo

Syft

Cybersecurity

Generates a software bill of materials from images, filesystems and archives

From
Free
Rated
-
Full reviewWebsite
Tenable Nessus logo

Tenable Nessus

Cybersecurity

Network vulnerability scanner

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Syft lockfile parsing can drop packages silently. An open issue filed in August 2026 reports the yarn v1 cataloguer returning 118 of 745 packages with no error raised, which means a complete bill of materials and an 84 percent incomplete one look identical to the caller.; Tenable Nessus nessus Professional is $4,790 for one year, sold as an annual licence rather than a per scan or usage based fee
  • They diverge on capability: Syft covers Multi-format output, Tenable Nessus covers Network scanning.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Syft and Tenable Nessus actually diverge.

Attributes where Syft and Tenable Nessus differ
AttributeSyftTenable Nessus
Pricing modelOpen source, no licence feesubscription
PlatformsmacOS, Linux, Windows, DockerWindows, Linux, Macos, Cloud
FoundedUnknown2002

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated), category (Cybersecurity).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Syft

  • Multi-format output
  • Broad ecosystem coverage
  • Binary classifiers
  • In-toto attestations
  • Library and CLI
  • Pairs with Grype

Only in Tenable Nessus

  • Network scanning
  • Vulnerability detection
  • Configuration assessment
  • Malware detection
  • Compliance checking
  • Cloud security assessment
  • Mobile scanning
  • API access

What people use each for

The jobs each tool is most often brought in to do.

Syft

  • Producing a bill of materials for a customer or regulator that requires onenot Tenable Nessus
  • Feeding an inventory into a vulnerability scanner rather than scanning images directlynot Tenable Nessus
  • Recording what shipped in a build so a future disclosure can be answered quicklynot Tenable Nessus
  • Public sector work where an SBOM is a contractual deliverablenot Tenable Nessus

Tenable Nessus

  • Vulnerability scanning of servers, network devices and web applicationsnot Syft
  • Configuration and compliance auditing against hardening benchmarksnot Syft
  • Point in time assessments by consultants and penetration testersnot Syft

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Syft

  • Lockfile parsing can drop packages silently. An open issue filed in August 2026 reports the yarn v1 cataloguer returning 118 of 745 packages with no error raised, which means a complete bill of materials and an 84 percent incomplete one look identical to the caller.
  • Fidelity varies sharply by ecosystem. Conan for C and C++, Haskell and Terraform get cataloguer support with no licence data, no dependency relationships and no file ownership, so a C and C++ shop gets the least from it.
  • Binary classification yields no licence or dependency metadata, and vendored or statically linked code is exactly where supply chain risk hides, so the blind spot and the risk overlap.
  • Incorrect CPE values and CPE collisions are recorded as open issues, and since Grype matches on CPE and PURL, an inventory error becomes a false negative in the security report downstream.
  • An inventory is not a risk assessment. Even a perfect bill of materials says a vulnerable version is present, never that the vulnerable function is called, and the triage burden lands entirely on the reader.

Tenable Nessus

  • Nessus Professional is $4,790 for one year, sold as an annual licence rather than a per scan or usage based fee
  • Support beyond the base entitlement costs an extra $400 per year for Advanced Support with 24x365 phone and chat access
  • The on demand training course is a separate $275 purchase for a single person for one year
  • Multi year discounts require paying for two or three years up front

Pricing, plan by plan

Syft

Free
  • SyftFree
    • Apache-2.0
    • No usage limits
    • Community support
  • Anchore Enterprise$undefined/year
    • Policy enforcement and reporting
    • Federal and commercial tiers
    • Pricing not published, quoted on request

Tenable Nessus

Free
  • Nessus EssentialsFree
    • Up to 16 ips
    • Network scanning
    • Vulnerability assessment
  • Nessus Professional$2600/year
    • Unlimited targets
    • Enterprise features
    • Advanced analytics
  • Nessus Expert$5200/year
    • All Professional features
    • Cloud integration
    • Advanced reporting

Which should you pick?

Choose Syft if

  • You need multi-format output.
  • You want to start without paying.
  • You work on macOS, Linux, Windows, Docker.
  • You also want broad ecosystem coverage.
Syft review

Choose Tenable Nessus if

  • You need network scanning.
  • You want to start without paying.
  • You work on Windows, Linux, Macos, Cloud.
  • You also want vulnerability detection.
Tenable Nessus review

Questions people ask

Is Syft or Tenable Nessus better?
Neither clearly leads. Syft starts at Free and Tenable Nessus at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Syft or Tenable Nessus?
Syft starts at Free and Tenable Nessus at Free.
Does Syft or Tenable Nessus run on more platforms?
Syft runs on macOS, Linux, Windows, Docker. Tenable Nessus runs on Windows, Linux, Macos, Cloud.
Can I use Syft for free?
Both have a free tier, so you can try either at no cost before committing.
What is Syft best used for?
Syft is most often used for producing a bill of materials for a customer or regulator that requires one, feeding an inventory into a vulnerability scanner rather than scanning images directly, recording what shipped in a build so a future disclosure can be answered quickly, public sector work where an sbom is a contractual deliverable. Of those, producing a bill of materials for a customer or regulator that requires one and feeding an inventory into a vulnerability scanner rather than scanning images directly are not what Tenable Nessus is typically brought in for.
What can Syft do that Tenable Nessus cannot?
Syft covers Multi-format output, Broad ecosystem coverage, Binary classifiers, In-toto attestations. Tenable Nessus covers Network scanning, Vulnerability detection, Configuration assessment, Malware detection.

Answered from the vendors’ own pages

Syft: Does Syft find vulnerabilities?

No. It produces an inventory. Grype, from the same company, matches that inventory against vulnerability feeds. They are separate tools and the distinction is frequently lost.

Tenable Nessus: What are the three Nessus offerings?

Nessus Essentials is a free introductory offering for educators, students, and career starters, limited to 16 IPs for scanning. Nessus Professional is designed for consultants and SMBs, providing unlimited IT scans across any location. Nessus Expert is the premium offering extending Professional with web application scanning, infrastructure-as-code scanning, and external attack surface assessment up to 5 domains.

Source
Syft: Does anything in the Anchore stack do reachability analysis?

No. Neither Syft, Grype nor the commercial Anchore platform performs call graph or reachability analysis, so none of them tells you whether a vulnerable code path is actually invoked.

Tenable Nessus: What OS platforms does Nessus support?

Nessus runs on Debian/Kali Linux, Fedora, FreeBSD, Mac OS X, Red Hat/CentOS, SUSE Linux, Ubuntu, and various Windows versions including Server 2008, 2012, and Windows 7-10.

Source
Syft: Is it a CNCF or OpenSSF project?

No. It is single-vendor open source owned by Anchore, with no foundation governance. That is a different licence risk profile from Sigstore.

Tenable Nessus: Can I use Nessus to scan third-party networks as a consultant?

Yes, Tenable permits you to use Nessus to scan third-party networks. Nessus Professional is ideal for consultants.

Source
Syft: What does Anchore Enterprise cost?

Not published. The pricing page is contact-sales only, with named but unpriced commercial and federal tiers.

Tenable Nessus: Can Nessus perform PCI external scanning?

Yes, you can use Nessus Professional to perform external network scans as required by the PCI DSS 11.2.2 requirement.

Source
Syft: How do I know my SBOM is complete?

You largely cannot, which is the honest answer. Silent partial parsing is a known open defect, so a bill of materials used for compliance should be spot-checked against a known dependency list.

Tenable Nessus: What additional features does Nessus Expert provide?

Web application scanning, which is dynamic application security testing (DAST) providing comprehensive visibility and insight into web application security issues; scanning code repositories for vulnerabilities; and assessing external attack surface with subdomain discovery.

Source
Tenable Nessus: What support options exist for Nessus Professional?

Standard Support includes software upgrades, patches, plugin access, and 24x7 support via chat and community portal. Advanced Support adds 24x7 phone access and committed SLAs: P1 less than 2 hours, P2 less than 4 hours, P3 less than 12 hours, P4 less than 24 hours.

Source
Tenable Nessus: How frequently are Nessus plugins updated?

Nessus plugins are updated daily, based on when vendors and security research sites publish new vulnerabilities.

Source
Tenable Nessus: How does licensing work in virtual machine environments?

Whether you are using Nessus in a physical or a virtual environment, the IP addresses or hosts that you are scanning from must be licensed.

Source
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