CVE-2026-21571: This Critical severity OS Command Injection vulnerability was introduced in versions 9.6.0, 10.0.0, 10.1.0, 10

This month

HIGH 8.8UPGRADE

CVE-2026-21571 is a high-severity flaw (CVSS 8.8) affecting bamboo. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

This Critical severity OS Command Injection vulnerability was introduced in versions 9.6.0, 10.0.0, 10.1.0, 10.2.0, 11.0.0, 11.1.0, 12.0.0, and 12.1.0 of Bamboo Data Center. This RCE (Remote Code Execution) vulnerability, with a CVSS Score of 9.4 and a CVSS Vector of CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H allows an authenticated attacker to execute commands on the remote system, which has high impact to confidentia

Why this priority

High severity

A fixed release or distro patch exists.

Risk facts

CVSS score	8.8 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	1.3% (top 29%)
CISA exploited list	No
Weakness	CWE-78
Published	2026-04-21
Last modified	2026-10-26

Publisher (CNA): Atlassian · Vendor: atlassian

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-21 17:16 UTCPublished CVE record published
2026-10-26 22:10 UTCUpdated Record last modified

atlassian bamboo UPGRADE

Affected: >= 9.6.2 and < 9.6.25 · >= 10.0.0 and < 10.2.18 · >= 11.0.0 and < 12.1.6

Fixed in: 9.6.25, 10.2.18, 12.1.6

Safe to downgrade to: a release before 9.6.2

1. Check installed version

apt-cache policy bamboo || rpm -q bamboo || bamboo --version

2. UPGRADE to 9.6.25 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade bamboo

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade bamboo

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 9.6.2 (Debian / Ubuntu)

apt-cache madison bamboo sudo apt install bamboo=<VERSION_BEFORE_9.6.2> sudo apt-mark hold bamboo

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list bamboo sudo dnf downgrade bamboo-<VERSION_BEFORE_9.6.2> sudo dnf versionlock add bamboo

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-21571?

bamboo: upgrade to 9.6.25, 10.2.18, 12.1.6. Exact commands for each OS are on this page.

Is CVE-2026-21571 being exploited?

CVE-2026-21571 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-21571 affect?

CVE-2026-21571 affects bamboo. Severity is high (CVSS 8.8). This Critical severity OS Command Injection vulnerability was introduced in versions 9.6.0, 10.0.0, 10.1.0, 10.2.0, 11.0.0, 11.1.0, 12.0.0, and 12.1.0 of Bamboo Data Center. This RCE (Remote Code Execution) vulnerability, with a CVSS S

How urgent is CVE-2026-21571?

Priority 49/100. High severity

Related CVEs

CVE-2026-21584 HIGH 8.1 UPGRADE This High severity Improper Authorization vulnerability was introduced in versions 10.0.0, 10.1.0, 10.2.0, 11.

References

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