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vulnerabilities
You Won’t Hear About These, Even In Myths (Atlassian Jira, Confluence (and more) Pre-Auth Arbitrary File Read CVE-2026-21589)
CVE-2026-21589 affects multiple Atlassian products including Jira, Confluence, Bitbucket, Bamboo, Crowd, Crucible, and Fisheye through a pre-authentication arbitrary file read vulnerability in the atlassian-plugins-webresource library. The flaw exploits path traversal via double colon (::) encoding to read sensitive files from the application webroot, including WEB-INF directory contents. When Atlassian Crowd is configured for identity management, attackers can extract Crowd credentials from the crowd.properties file and achieve complete administrative compromise of the Crowd instance and all integrated Atlassian applications.
Why it matters: Organizations running on-premises deployments of Jira, Confluence, Bitbucket, or other affected Atlassian products must patch immediately: hundreds of thousands of instances are exposed to unauthenticated file read and potential account takeover if Crowd is integrated. Security practitioners should prioritize updating to the fixed versions listed (Jira Software 9.12.40, 10.3.26, or 11.3.12; Confluence 9.2.26, 10.2.19; and others) and verify whether Crowd is in use, as the attack chain enables complete administrative access.
- Source published
- First seen by Cybersecurity Tracker
Source attribution
Correction
Correction recorded as of .
vulnerabilities
You Won’t Hear About These, Even In Myths (Atlassian Jira, Confluence (and more) Pre-Auth Arbitrary File Read CVE-2026-21589)
Atlassian published a critical out-of-band security advisory for CVE-2026-21589, affecting Bitbucket, Confluence, Jira, Bamboo, Crowd, Crucible, and Fisheye Data Center installations, stemming from a shared library flaw in atlassian-plugins-webresource. The vulnerability allows unauthenticated arbitrary file read via path traversal using double-colon bypass syntax on web resource routes, enabling attackers to extract sensitive configuration files including Crowd identity management credentials stored in WEB-INF directories. When Crowd integration is configured, attackers can leverage leaked credentials to access the centralized identity platform and create administrative accounts across the entire Atlassian deployment stack.
Why it matters: Organizations running any affected Atlassian Data Center product on-premises or cloud must prioritize immediate patching; hundreds of thousands of instances are estimated vulnerable, and pre-authentication file read combined with common Crowd configurations leads to full administrative compromise of user directories and connected applications.
- Source published
- First seen by Cybersecurity Tracker
Source attribution
Correction
Correction recorded as of .
vulnerabilities
You Won’t Hear About These, Even In Myths (Atlassian Jira, Confluence (and more) Pre-Auth Arbitrary File Read CVE-2026-21589)
CVE-2026-21589 is a pre-authentication arbitrary file read vulnerability affecting multiple Atlassian products including Jira, Confluence, Bitbucket, Bamboo, Crowd, Crucible, and Fisheye through a flaw in the atlassian-plugins-webresource library. The vulnerability exploits path traversal using double colon (::) encoding to bypass file access restrictions and read sensitive files from the application webroot, including WEB-INF configuration files. When Atlassian Crowd is integrated for authentication, leaked credentials from the crowd.properties file allow attackers to access the identity management system with application privileges and create new administrator accounts.
Why it matters: Organizations running any affected Atlassian product on-premises must patch immediately, as an unauthenticated attacker can read configuration files and potentially compromise the entire Atlassian stack by escalating through Crowd if it is deployed. Administrators should verify all deployed Atlassian product versions against the fixed versions and apply updates for Bitbucket, Confluence, Jira Software, Jira Service Management, Bamboo, Crowd, Crucible, and Fisheye.
- Source published
- First seen by Cybersecurity Tracker
Source attribution
Correction
Correction recorded as of .
vulnerabilities
You Won’t Hear About These, Even In Myths (Atlassian Jira, Confluence (and more) Pre-Auth Arbitrary File Read CVE-2026-21589)
CVE-2026-21589 is a pre-authentication arbitrary file read vulnerability affecting multiple Atlassian products, including Jira, Confluence, Bitbucket, Bamboo, Crowd, Crucible, and Fisheye, through a flaw in the atlassian-plugins-webresource library that fails to properly sanitize path traversal using double colons (::) as slash escapes. Researchers demonstrated reading sensitive files from the WEB-INF directory, including crowd.properties credentials that enable direct access to Atlassian Crowd identity management systems with administrator privileges. Atlassian released patches on October 5, with fixed versions available for all affected products, and the vulnerability carries a CVSS 4.0 score of 9.3 with no authentication required.
Why it matters: Organizations running any on-premises Atlassian product (Jira, Confluence, Bitbucket, Bamboo, Crowd, Crucible, Fisheye) must patch immediately, as unauthenticated attackers can read WEB-INF files, and where Crowd is configured, can extract plaintext application credentials and compromise all connected identity management and user administration.
- Source published
- First seen by Cybersecurity Tracker