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Cybersecurity · head to head

Cosign vs Tenable

Cosign logo

Cosign

Cybersecurity

Signs and verifies container images and artifacts, with or without managing keys

From
Free
Rated
-
Full reviewWebsite
Tenable logo

Tenable

Cybersecurity

AI-powered exposure management platform for unified security visibility

From
$3500/year
Rated
-
Full reviewWebsite

The short version

  • Only Cosign has a free tier, so it costs nothing to try first.
  • Each has a real cost: Cosign keyless signing inherits every weakness of the identity provider behind it. Sigstore’s own threat model states that if an identity provider is compromised, Sigstore will issue certificates to those identities, so a compromised account produces perfectly valid signatures.; Tenable pricing starts at $3500/year for Tenable One VM, expensive for small organizations
  • They diverge on capability: Cosign covers Keyless signing, Tenable covers Unified attack surface mapping.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Cosign and Tenable actually diverge.

Attributes where Cosign and Tenable differ
AttributeCosignTenable
Starting priceFree$3500/year
Pricing modelOpen source, no licence feesubscription
Free tierYesNo
PlatformsmacOS, Linux, Windows, DockerCloud, Web

Identical on both: 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 Cosign

  • Keyless signing
  • Key and KMS signing
  • Registry-native storage
  • In-toto attestations
  • Offline verification
  • Trusted root and signing config

Only in Tenable

  • Unified attack surface mapping
  • Exposure intelligence enrichment
  • Tenable Hexa AI orchestration
  • Cloud Exposure (CNAPP)
  • OT Exposure
  • Identity Exposure
  • Vulnerability Management
  • Attack Surface Management

What people use each for

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

Cosign

  • Signing container images in a build pipeline without managing long-lived private keysnot Tenable
  • Attaching a signed bill of materials to a release so consumers can verify its provenancenot Tenable
  • Meeting a customer or regulatory requirement for signed artifactsnot Tenable
  • Verifying third-party images before they enter an internal registrynot Tenable

Tenable

  • Comprehensive vulnerability scanning for enterprise networksnot Cosign
  • Cloud security monitoring and compliance for AWS, Azure, GCPnot Cosign
  • Identity and access management risk assessmentnot Cosign
  • Operational technology security for industrial systemsnot Cosign
  • Attack surface management for third-party risknot Cosign

Where each one falls short

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

Cosign

  • Keyless signing inherits every weakness of the identity provider behind it. Sigstore’s own threat model states that if an identity provider is compromised, Sigstore will issue certificates to those identities, so a compromised account produces perfectly valid signatures.
  • A signature proves who signed, never whether they should have. The documentation is explicit that Sigstore cannot determine authorisation, so every consumer must write and maintain their own identity and issuer policy or verification means nothing.
  • Nothing is enforced without an admission controller. Signing changes what you can prove, not what runs, and the official policy controller has a small maintainer base for a component sitting in a cluster admission path.
  • Upgrades break pipelines. Version 3 changed defaults, version 4 is announced as removing legacy functionality and roughly half the command line flags, and two official client libraries still lacked support for the new log format as of mid 2026.
  • Signatures do not expire. An artifact signed before a maintainer account was compromised and one signed after are indistinguishable unless somebody is actively monitoring the transparency log, and almost nobody is.

Tenable

  • Pricing starts at $3500/year for Tenable One VM, expensive for small organizations
  • Many enterprise features require custom quote and sales engagement
  • Cloud Exposure, OT Exposure, and other modules have no published pricing
  • Multi-year contracts common, limiting flexibility
  • Setup and configuration complexity for enterprise deployments

Pricing, plan by plan

Cosign

Free
  • CosignFree
    • Apache-2.0
    • Public Sigstore infrastructure free to use
    • No usage limits published

Tenable

$3500/year
  • Tenable One Vulnerability Management$3500/year
    • Per 100 assets
    • Multi-year discounts available
  • Tenable One Web App Scanning$3578/year
    • Per 5 FQDNs
    • Annual subscription
  • Nessus Professional$4790/year
    • Vulnerability scanning
    • Multi-year discounts available
    • Optional advanced support: $400/year
  • Nessus Expert$6790/year
    • Advanced vulnerability scanning
    • Multi-year discounts available
    • Optional advanced support: $400/year

Which should you pick?

Choose Cosign if

  • You need keyless signing.
  • You want to start without paying.
  • You work on macOS, Linux, Windows, Docker.
  • You also want key and kms signing.
Cosign review

Choose Tenable if

  • You need unified attack surface mapping.
  • You work on Cloud, Web.
  • You also want exposure intelligence enrichment.
Tenable review

Questions people ask

Is Cosign or Tenable better?
Neither clearly leads. Cosign starts at Free and Tenable at $3500/year, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Cosign or Tenable?
Cosign has a free tier; the other does not. Paid plans start at Free for Cosign and $3500/year for Tenable.
Does Cosign or Tenable run on more platforms?
Cosign runs on macOS, Linux, Windows, Docker. Tenable runs on Cloud, Web.
Can I use Cosign for free?
Yes. Cosign has a free tier, so you can try it without paying. Tenable starts at $3500/year.
What is Cosign best used for?
Cosign is most often used for signing container images in a build pipeline without managing long-lived private keys, attaching a signed bill of materials to a release so consumers can verify its provenance, meeting a customer or regulatory requirement for signed artifacts, verifying third-party images before they enter an internal registry. Of those, signing container images in a build pipeline without managing long-lived private keys and attaching a signed bill of materials to a release so consumers can verify its provenance are not what Tenable is typically brought in for.
What can Cosign do that Tenable cannot?
Cosign covers Keyless signing, Key and KMS signing, Registry-native storage, In-toto attestations. Tenable covers Unified attack surface mapping, Exposure intelligence enrichment, Tenable Hexa AI orchestration, Cloud Exposure (CNAPP).

Answered from the vendors’ own pages

Cosign: Does Cosign tell me if an image is vulnerable?

No. It has no vulnerability knowledge whatsoever. It can carry an SBOM as a signed attestation but never reads it. Pair it with a scanner.

Tenable: How is Tenable One pricing structured?

Tenable One Vulnerability Management costs $3500/year per 100 assets. Web App Scanning is $3578/year per 5 FQDNs. Multi-year discounts are available.

Source
Cosign: Is signing alone enough?

No. Verification is a command somebody runs. Without an admission controller enforcing it, an unsigned image still runs.

Tenable: What is the difference between Nessus Professional and Nessus Expert?

Nessus Professional costs $4790/year and provides core vulnerability scanning. Nessus Expert costs $6790/year and offers advanced scanning capabilities.

Source
Cosign: What does a bare cosign verify actually prove?

Very little. Without a pinned certificate identity and OIDC issuer, it accepts a valid signature from any identity at all.

Tenable: Are custom support and training available for Tenable?

Yes. Optional advanced support is available for $400/year. Training courses range from $275-$385/year.

Source
Cosign: What is the risk of keyless signing?

Your OIDC provider becomes the root of trust. Compromise of that account yields genuine, verifiable signatures, so account security is the control that matters.

Cosign: Should we expect breaking changes?

Yes. Version 4 is announced to remove roughly half the flags, and a post-quantum migration is named as a further breaking change after that.

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