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CVE-2026-21589

This is a vulnerability in Bitbucket Data Center, Confluence Data Center, Jira Service Management Data Center, Jira Software Data Center, Ba

Published
Last modified
published
Listed in CISA KEV
Actively exploited
13 proofs of concept on GitHub, 1 Nuclei template
  • Exploitation: active
  • Automatable: no
  • Technical impact: total

Summary

This vulnerability affects Atlassian Data Center products, including Bitbucket, Confluence, Jira Software, Jira Service Management, Bamboo, Crowd, Crucible, and Fisheye. It allows an unauthenticated remote attacker to access specific files within the web application root directory, which could expose sensitive information in some configurations.

Summarized by anthropic/claude-haiku-5.5. Verify details against the original sources.

Read the original description

This is a vulnerability in Bitbucket Data Center, Confluence Data Center, Jira Service Management Data Center, Jira Software Data Center, Bamboo Data Center. Crowd Data Center, Crucible and Fisheye. This Arbitrary File Access vulnerability allows an unauthenticated attacker to access specific files within the web application root directory in affected versions. Exploitation requires prior knowledge of the target file's exact name and path; this vulnerability does not allow attackers to enumerate or list directory contents. In some configurations, there may be some sensitive files that make this highly severe. This vulnerability allows an unauthenticated remote attacker to access specific files within the web application root directory in affected versions. The vulnerability must be addressed for affected versions of: -- Bitbucket Data Center, introduced in version >= 4.6.0, fix versions: 9.4.26, 10.2.8, 10.5.1 -- Confluence Data Center, introduced in version >= 5.10.0, fix versions 9.2.26, 10.2.19 -- Crowd Data Center, introduced in version >= 2.11.0, fix versions 6.3.7, 7.0.3, 7.1.7, 7.2.4 -- Jira Software Data Center, introduced in version >= 7.1.0, fix versions 9.12.40, 10.3.26, 11.3.12 -- Jira Service Management Data Center, introduced in version >= 3.1.0, fix versions 5.12.40, 10.3.26, 11.3.12 -- Bamboo Data Center >= 7.0.1, fix versions 10.2.24, 12.1.12 -- Crucible, fix versions 4.9.15 -- Fisheye, fix version 4.9.15 -- Exploitation requires prior knowledge of the target file's exact name and path. The vulnerability does not include the capability to enumerate or list directory contents.

Timeline

  1. CVE published
  2. Added to CISA KEV

    CISA has evidence of exploitation in the wild

  3. CISA SSVC assessment

    Exploitation: active · Automatable: no · Technical impact: total

  4. CISA remediation deadline

    Due date for US federal agencies to patch

  5. EPSS reached 10%

    FIRST estimates at least a 10% chance of exploitation in the next 30 days

  6. Record last updated

Affected versions

  • Atlassian Bamboo Data Center

    Version range not reported

  • Atlassian Bitbucket Data Center

    Version range not reported

  • Atlassian Confluence Data Center

    Version range not reported

  • Atlassian Crowd Data Center

    Version range not reported

  • Atlassian Crucible Data Center

    Version range not reported

  • Atlassian Fisheye Data Center

    Version range not reported

  • Atlassian Jira Service Management Data Center

    Version range not reported

  • Atlassian Jira Software Data Center

    Version range not reported

References 22

jira.atlassian.com

GitHub · projectdiscovery/nuclei-templates

GitHub · 0xredash/CVE-2026-21589

GitHub · BimBoxH4/CVE-2026-21589

GitHub · CompleTech-Security/atlassian-cve-2026-21589-check

GitHub · MarcusProgram/CVE-2026-21589

GitHub · aduli198/CVE-2026-21589

GitHub · gotr00t0day/CVE-2026-21589

GitHub · murrez/CVE-2026-21589

GitHub · renzi25031469/CVE-2026-21589

GitHub · rxsklife/CVE-2026-21589

GitHub · tc4dy/CVE-2026-21589-PoC-Exploit

GitHub · watchtowrlabs/watchTowr-vs-Atlassian-CVE-2026-21589

GitHub · webserverdude/f5_CVE-2026-21589_mitigation

GitHub · ynsmroztas/AtlasSniper

FAQ

Questions about CVE-2026-21589

What does this mean?

An unauthenticated attacker can access specific files within the web application root directory of the affected Data Center products.Source: jira.atlassian.com, jira.atlassian.com, jira.atlassian.com

Am I affected, and how do I check?

The advisory lists all Bamboo, Bitbucket, and Confluence Data Center versions before the fixed versions as affected, and also names Crowd, Crucible, Fisheye, Jira Service Management, and Jira Software Data Center. To check a version, compare the installed version against the fixed versions listed in Atlassian's advisory.Source: jira.atlassian.com, jira.atlassian.com, jira.atlassian.com

What should I do about it?

Atlassian recommends upgrading to one of the fixed versions listed in its advisory. The specific fixed version numbers are not in the checked facts, so confirm them in the advisory.Source: jira.atlassian.com, jira.atlassian.com, jira.atlassian.com

Is it being exploited?

Yes. CISA added it to its Known Exploited Vulnerabilities catalog on 2026-10-15, which means it has evidence of attacks. Public exploit code exists (a Nuclei template, a proof of concept on GitHub).Source: cisa.gov, cve.now feed data

What if there's no patch?

Block requests matching the regex pattern given in the advisory at a web application firewall or proxy, or use Tomcat's RewriteValve.Source: jira.atlassian.com, jira.atlassian.com, jira.atlassian.com