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Cybersecurity · head to head

Cosign vs Qualys VMDR

Cosign logo

Cosign

Cybersecurity

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

From
Free
Rated
-
Full reviewWebsite
Qualys VMDR logo

Qualys VMDR

Cybersecurity

Cloud-delivered vulnerability management licensed per asset, using scanner appliances and a lightweight agent.

From
$3/month
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.; Qualys VMDR licensing is per asset and each capability is its own subscription, so patch management, endpoint detection, web application scanning, container security and policy compliance are separate line items, and the platform demonstrated in a proof of concept is rarely the platform in the quote.
  • They diverge on capability: Cosign covers Keyless signing, Qualys VMDR covers Cloud Agent.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Cosign and Qualys VMDR actually diverge.

Attributes where Cosign and Qualys VMDR differ
AttributeCosignQualys VMDR
Starting priceFree$3/month
Pricing modelOpen source, no licence feesubscription
Free tierYesNo
PlatformsmacOS, Linux, Windows, DockerWeb, Cloud, Api
FoundedUnknown1999

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 Qualys VMDR

  • Cloud Agent
  • Scanner appliances
  • Authenticated scanning
  • TruRisk scoring
  • Asset inventory
  • Patch Management
  • Cloud connectors
  • Container sensor

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 Qualys VMDR
  • Attaching a signed bill of materials to a release so consumers can verify its provenancenot Qualys VMDR
  • Meeting a customer or regulatory requirement for signed artifactsnot Qualys VMDR
  • Verifying third-party images before they enter an internal registrynot Qualys VMDR

Qualys VMDR

  • A hybrid workforce where scheduled network scans miss most laptops and continuous agent-based assessment is the only way to get real coveragenot Cosign
  • PCI DSS external scanning where an approved scanning vendor report is a contractual requirementnot Cosign
  • An estate spanning datacentre, multiple public clouds and endpoints that needs one vulnerability view rather than three toolsnot Cosign
  • Organisations replacing a manual patch-verification process with agent-reported evidence that a fix actually landednot 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.

Qualys VMDR

  • Licensing is per asset and each capability is its own subscription, so patch management, endpoint detection, web application scanning, container security and policy compliance are separate line items, and the platform demonstrated in a proof of concept is rarely the platform in the quote.
  • Ephemeral cloud instances consume asset entitlement until they age out of inventory, so an autoscaling group that creates and destroys hosts hourly can burn licence capacity on machines that existed for minutes, and controlling that means tuning purge policies rather than tuning the cloud.
  • Authenticated scanning produces materially better results than unauthenticated, but it requires storing and rotating privileged credentials for every target platform, which is a security project in its own right, and teams that skip it receive reports full of unconfirmed potential findings that nobody trusts.
  • The console is a set of modules with separate interfaces, search syntaxes and report engines, so an analyst moving between vulnerability management, policy compliance and web application scanning learns each one, and cross-module reporting usually ends in a spreadsheet or a script against the API.
  • The tool surfaces findings far faster than any organisation can remediate them, and it does not solve the ownership problem: without an agreed prioritisation policy and a named owner in IT operations, a first scan producing tens of thousands of findings becomes a dashboard that everyone learns to ignore.

Pricing, plan by plan

Cosign

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

Qualys VMDR

$3/month
  • VMDR$3/month
    • Per asset
    • Vulnerability scanning
    • Detection
  • VMDR+$5/month
    • All VMDR features
    • Advanced analytics
    • Cloud integration
  • VMDR Complete$7/month
    • All VMDR+ features
    • Threat intel
    • Response automation

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 Qualys VMDR if

  • You need cloud agent.
  • You work on Web, Cloud, Api.
  • You also want scanner appliances.
Qualys VMDR review

Questions people ask

Is Cosign or Qualys VMDR better?
Neither clearly leads. Cosign starts at Free and Qualys VMDR at $3/month, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Cosign or Qualys VMDR?
Cosign has a free tier; the other does not. Paid plans start at Free for Cosign and $3/month for Qualys VMDR.
Does Cosign or Qualys VMDR run on more platforms?
Cosign runs on macOS, Linux, Windows, Docker. Qualys VMDR runs on Web, Cloud, Api.
Can I use Cosign for free?
Yes. Cosign has a free tier, so you can try it without paying. Qualys VMDR starts at $3/month.
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 Qualys VMDR is typically brought in for.
What can Cosign do that Qualys VMDR cannot?
Cosign covers Keyless signing, Key and KMS signing, Registry-native storage, In-toto attestations. Qualys VMDR covers Cloud Agent, Scanner appliances, Authenticated scanning, TruRisk scoring.

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.

Qualys VMDR: Agent or scanner: which do I need?

Usually both. The agent covers endpoints and servers you control and gives continuous data; scanners cover devices you cannot install an agent on, such as network gear, printers and appliances, and provide the external perimeter view.

Cosign: Is signing alone enough?

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

Qualys VMDR: Does it patch as well as detect?

Yes, through the Patch Management module, which is a separate subscription using the same agent. Core VMDR detects and prioritises but does not deploy fixes.

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.

Qualys VMDR: How are assets counted for licensing?

By the number of assets in inventory, which includes cloud instances and containers depending on the modules in use. Short-lived cloud assets count until they are purged, so purge settings directly affect what you consume.

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.

Qualys VMDR: Can I keep the data in a specific region?

Yes. Qualys operates several regional platform instances and you choose which one your subscription lives on. Moving between them later is not trivial, so decide before onboarding.

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.

Qualys VMDR: Does it scan web applications?

Web Application Scanning is a separate module licensed per application, not part of core VMDR, and it is a dynamic scanner with the usual limits around authenticated flows in single-page applications.

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