Vulnerability in Atlassian (CVE-2026-21587)
Summary
Vulnerability in Atlassian (CVE-2026-21587). Risk of unauthorized operations or information disclosure.
Original description
The description as published by the source.
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.
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-21587 has been found in Atlassian.
Risk of unauthorized operations or information disclosure. CVSS score: 7.1/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Atlassian CVE-2026-21587" on the vendor's site.
CVE-2026-21587 (Atlassian) — CWE-285 / CVSS v3 7.1
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-285) exists in Atlassian.
Check the vendor advisory for the affected versions of Atlassian.
Severity: High (CVSS 7.1/10). Risk of unauthorized operations or information disclosure.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで Atlassian を使っているサービスとバージョンを洗い出す。
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2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
References
- web confluence.atlassian.com
- web jira.atlassian.com
- web nvd.nist.gov
- web github.com