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Saml Single Sign OnApplication · Atlassian

CVE-2021-37843

CRITICAL · 9.8 CVSS v3.1 Published 2021-08-02
Fix available
A fix is available. Upgrade to 2.5.9 / 3.5.6 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
The resolution SAML SSO apps for Atlassian products allow a remote attacker to login to a user account when only the username is known (i.e., no other authentication is provided). The fixed versions are for Jira: 3.6.6.1, 4.0.12, 5.0.5; for Confluence 3.6.6, 4.0.12, 5.0.5; for Bitbucket 2.5.9, 3.6.6, 4.0.12, 5.0.5; for Bamboo 2.5.9, 3.6.6, 4.0.12, 5.0.5; and for Fisheye 2.5.9.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

This is a critical authentication bypass vulnerability in SAML SSO apps for multiple Atlassian products (Jira, Confluence, Bitbucket, Bamboo, Fisheye). The flaw allows a remote attacker to log into any user account using only the username, bypassing all other authentication factors required by the SAML SSO implementation.

MitigationImmediately upgrade the SAML SSO app to the fixed versions: Jira 3.6.6.1/4.0.12/5.0.5, Confluence 3.6.6/4.0.12/5.0.5, Bitbucket 2.5.9/3.6.6/4.0.12/5.0.5, Bamboo 2.5.9/3.6.6/4.0.12/5.0.5, and Fisheye 2.5.9.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Saml Single Sign OnApplication
Affected:< 2.5.9< 3.5.6< 3.6.6.1>= 3.0.0, < 3.6.6>= 3.6.0, < 3.6.6.1>= 4.0.0, < 4.0.12>= 5.0.0, < 5.0.5

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify your Atlassian product
    Determine which Atlassian product is running (Jira, Confluence, Bitbucket, Bamboo, or Fisheye) and note the product version. This is typically visible in the application footer or administration console.
    Affected if The product is one of Jira, Confluence, Bitbucket, Bamboo, or Fisheye with SAML SSO app installed
  2. Check if SAML SSO app is installed
    Navigate to the Atlassian application administration panel, then to the 'Manage apps' or 'Add-ons' section. Look for an app named 'SAML Single Sign On' or similar SAML SSO implementation.
    Affected if The SAML SSO app is listed as installed in the add-ons management console
  3. Determine the installed SAML SSO app version
    In the 'Manage apps' or 'Add-ons' section, find the SAML SSO app and locate its version number displayed in the app details or listing.
    Affected if The displayed version number matches any of these ranges: < 2.5.9, < 3.5.6, >= 3.0.0 and < 3.6.6, >= 3.6.0 and < 3.6.6.1, >= 4.0.0 and < 4.0.12, or >= 5.0.0 and < 5.0.5
  4. Verify SAML SSO authentication is enabled
    Check the SAML SSO app configuration in the administration console to confirm that SAML single sign-on is actively configured and enabled for user authentication.
    Affected if SAML SSO is configured and enabled as an authentication method

You are affected if the SAML SSO app version falls within any of the vulnerable version ranges AND SAML SSO authentication is enabled in your Atlassian product.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 2.5.9 / 3.5.6 / 3.6.6 or later
Fixed in 2.5.93.5.63.6.6
Interim mitigation

Immediately upgrade the SAML SSO app to the fixed versions: Jira 3.6.6.1/4.0.12/5.0.5, Confluence 3.6.6/4.0.12/5.0.5, Bitbucket 2.5.9/3.6.6/4.0.12/5.0.5, Bamboo 2.5.9/3.6.6/4.0.12/5.0.5, and Fisheye 2.5.9.

Recommended fix High confidence

Upgrade to SAML SSO app version 5.0.5 (latest stable fixed release) for all products, or minimum fixed version per product: Jira 3.6.6.1, Confluence 3.6.6, Bitbucket 2.5.9, Bamboo 2.5.9, Fisheye 2.5.9

  1. 1. Identify which Atlassian product (Jira, Confluence, Bitbucket, Bamboo, or Fisheye) is running the SAML Single Sign-On app
  2. 2. Check the current version of the SAML SSO app installed on the Atlassian product
  3. 3. Determine the version of the Atlassian product itself to ensure compatibility with the fixed SSO app versions
  4. 4. For Jira: upgrade to version 3.6.6.1, 4.0.12, or 5.0.5
  5. 5. For Confluence: upgrade to version 3.6.6, 4.0.12, or 5.0.5
  6. 6. For Bitbucket: upgrade to version 2.5.9, 3.6.6, 4.0.12, or 5.0.5
  7. 7. For Bamboo: upgrade to version 2.5.9, 3.6.6, 4.0.12, or 5.0.5
  8. 8. For Fisheye: upgrade to version 2.5.9
Caveat Review release notes for version 3.x/4.x/5.x upgrades to check for configuration changes, deprecated features, or Atlassian product version compatibility requirements before upgrading

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Saml Single Sign On Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing8.0 h
  • Review / QA4.0 h
24.0 hours of engineering $4,160
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-37843 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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