This High severity Improper Authorization vulnerability was introduced in versions 10.0.0, 10.1.0, 10.2.0, 11.0.0, 12.0.0, and 12.1.0 of Bamboo Data Center. This Improper Authorization vulnerability, with a CVSS Score of 7.6, 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 Bamboo 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: * Bamboo Data Center 10.2: Upgrade to a release greater than or equal to 10.2.22 * Bamboo Data Center 12.1: Upgrade to a release greater than or equal to 12.1.10 See the release notes (https://confluence.atlassian.com/bambooreleases/bamboo-release-notes-1189793869.html). You can download the latest version of Bamboo Data Center from the download center (https://www.atlassian.com/software/bamboo/download-archives). This vulnerability was reported via our Penetration Testing program.
CVE-2026-21584
This high-severity CVE scores 7.6 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4%, top 71% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
- High severity, but no confirmed exploitation yet
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 7.6
- EG Score
- 7.6(medium)
- EG Risk
- 34(Track)EG Risk 34/100SSVC: Track
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity76% × 45%Exploitation0% × 40%Automatability0% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- 0%
- EPSS %ILE
- 29%
- KEV
- Not listed
Published
August 18, 2026
Last Modified
August 20, 2026
Advisory Details (2)
Auto-updated Aug 18, 2026Security Bulletin - August 18 2026 | Atlassian Support | Atlassian Documentation
https://confluence.atlassian.com/pages/viewpage.action?pageId=1821999768Vendor Advisories for CVE-2026-21584(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Data Freshness Timeline
(refreshed 19× in last 7d / 19× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-08-21 07:06 UTCEG score recompute
- 2026-08-21 07:05 UTCGHSA enrichment
- 2026-08-20 22:55 UTCEPSS rescore
- 2026-08-20 19:18 UTCEG score recompute
- 2026-08-20 19:18 UTCGHSA enrichment
- 2026-08-20 18:52 UTCEG score recompute
- 2026-08-20 18:52 UTCGHSA enrichment
- 2026-08-20 16:09 UTCGHSA enrichment
- 2026-08-20 04:20 UTCEG score recompute
- 2026-08-20 04:20 UTCGHSA enrichment
- 2026-08-20 04:08 UTCEG score recompute
- 2026-08-20 04:08 UTCGHSA enrichment
- 2026-08-19 21:59 UTCEG score recompute
- 2026-08-19 21:59 UTCGHSA enrichment
- 2026-08-19 17:03 UTCEPSS rescore
- 2026-08-19 10:12 UTCGHSA enrichment
- 2026-08-18 22:23 UTCEG score recompute
- 2026-08-18 22:04 UTCEG score recompute
- 2026-08-18 22:04 UTCMITRE cvelistV5first tracked
Frequently asked(5)
What is CVE-2026-21584?
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What is the CVSS score of CVE-2026-21584?
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Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-21584
Is Your Infrastructure Affected by CVE-2026-21584?
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