8.1

CVE-2026-21584: atlassian bamboo Improper Authorization

Analyzed
Published 18-08-2026Last modified 28-08-2026

Vulnerability summary

CVE-2026-21584 is a high (CVSS 8.1) Improper Authorization vulnerability in atlassian bamboo. EPSS estimates a 0.46% chance of exploitation in the next 30 days, higher than 39.9% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 7.6, network access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
8.1/10
010
High · v3.1 (NVD)
EPSS score
0.46%
0%100%
Low · +0.15 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Timeline

  1. 18-08-2026
    PublishedVulnerability first disclosed.
  2. 28-08-2026
    Last modifiedVulnerability information updated.

Description

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.

CVSS metrics

3 scores · 2 sources · 2 versions

EPSS trend

Probability

0.46%

Chance of exploitation in the next 30 days

Percentile

40%

Versus all other CVEs

30-day change

Increase +0.15 pp

From 0.31% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Atlassian2 products
  • bamboo≥ 10.0.0, < 10.2.22 | ≥ 11.0.0, < 12.1.10
  • bamboo data center12.1.0 to 12.1.9 | 12.0.0 to 12.0.2 | 11.0.0 to 11.0.8 | 10.2.0 to 10.2.21 | 10.1.0 to 10.1.1 | 10.0.0 to 10.0.3

1 vendor · 2 products

References

2 links