PatchTheCEVCVE-2026-21589: Atlassian Multiple Products Files or Directories Accessible to External Parties Vulnerability
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HIGH 7.5EXPLOITEDREMOTEUPGRADEUPGRADEUPGRADE
CVE-2026-21589 is a high-severity flaw (CVSS 7.5) affecting bitbucket data center, bitbucket server, confluence data center, reported as exploited in the wild. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
This is a vulnerability in Bitbucket Data Center, Confluence Data Center, Jira Service Management Data Center, Jira Software Data Center, Bamboo Data Center. Crowd Data Center, Crucible and Fisheye. This Arbitrary File Access vulnerability allows an unauthenticated attacker to access specific files within the web application root directory in affected versions. Exploitation requires prior knowledge of the target file's exact name and path; this v
Why this priority
- High severity
- EPSS top 4%: very likely to be exploited
- Exploited in the wild (CISA KEV)
- Public exploit reference
- Covered by 3 security sources
- Remotely exploitable, no login, no user action
A fixed release or distro patch exists.
Risk facts
| CVSS score | 7.5 (High) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 12.7% (top 4%) |
| CISA exploited list | Yes, fix due 2026-10-18 |
| Weakness | CWE-552 |
| Published | 2026-10-05 |
| Last modified | 2026-10-19 |
Am I affected?
Timeline
- Published CVE record published
- Exploited Added to the CISA Known Exploited Vulnerabilities list
- Deadline CISA due date for US federal agencies to patch
- Updated Record last modified
atlassian bitbucket data center UPGRADE
Affected: >= 7.17.0 and < 9.4.26 · >= 9.5.0 and < 10.2.8 · >= 10.3.0 and < 10.5.1
Fixed in: 9.4.26, 10.2.8, 10.5.1
Safe to downgrade to: a release before 7.17.0
1. Check installed version
apt-cache policy bitbucket-data-center || rpm -q bitbucket-data-center || bitbucket-data-center --version
2. UPGRADE to 9.4.26 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade bitbucket-data-center
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade bitbucket-data-center
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 7.17.0 (Debian / Ubuntu)
apt-cache madison bitbucket-data-center
sudo apt install bitbucket-data-center=<VERSION_BEFORE_7.17.0>
sudo apt-mark hold bitbucket-data-center
3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list bitbucket-data-center
sudo dnf downgrade bitbucket-data-center-<VERSION_BEFORE_7.17.0>
sudo dnf versionlock add bitbucket-data-center
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.
atlassian bitbucket server UPGRADE
Affected: >= 4.6.0 and <= 8.14.6
Fixed in: newer than 8.14.6
Safe to downgrade to: a release before 4.6.0
1. Check installed version
apt-cache policy bitbucket-server || rpm -q bitbucket-server || bitbucket-server --version
2. UPGRADE to newer than 8.14.6 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade bitbucket-server
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade bitbucket-server
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 4.6.0 (Debian / Ubuntu)
apt-cache madison bitbucket-server
sudo apt install bitbucket-server=<VERSION_BEFORE_4.6.0>
sudo apt-mark hold bitbucket-server
3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list bitbucket-server
sudo dnf downgrade bitbucket-server-<VERSION_BEFORE_4.6.0>
sudo dnf versionlock add bitbucket-server
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.
atlassian confluence data center UPGRADE
Affected: >= 5.10.0 and < 9.2.26 · >= 9.3.0 and < 10.2.19
Fixed in: 9.2.26, 10.2.19
Safe to downgrade to: a release before 5.10.0
1. Check installed version
apt-cache policy confluence-data-center || rpm -q confluence-data-center || confluence-data-center --version
2. UPGRADE to 9.2.26 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade confluence-data-center
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade confluence-data-center
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 5.10.0 (Debian / Ubuntu)
apt-cache madison confluence-data-center
sudo apt install confluence-data-center=<VERSION_BEFORE_5.10.0>
sudo apt-mark hold confluence-data-center
3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list confluence-data-center
sudo dnf downgrade confluence-data-center-<VERSION_BEFORE_5.10.0>
sudo dnf versionlock add confluence-data-center
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.
atlassian crowd UPGRADE
Affected: >= 2.11.0 and < 6.3.7 · >= 7.0.0 and < 7.0.3 · >= 7.1.0 and < 7.1.7 · >= 7.2.0 and < 7.2.4
Fixed in: 6.3.7, 7.0.3, 7.1.7, 7.2.4
Safe to downgrade to: a release before 2.11.0
1. Check installed version
apt-cache policy crowd || rpm -q crowd || crowd --version
2. UPGRADE to 6.3.7 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade crowd
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade crowd
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 2.11.0 (Debian / Ubuntu)
apt-cache madison crowd
sudo apt install crowd=<VERSION_BEFORE_2.11.0>
sudo apt-mark hold crowd
3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list crowd
sudo dnf downgrade crowd-<VERSION_BEFORE_2.11.0>
sudo dnf versionlock add crowd
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.
atlassian jira data center UPGRADE
Affected: >= 7.1.0 and < 9.12.40 · >= 9.13.0 and < 10.3.26 · >= 10.4.0 and < 11.3.12
Fixed in: 9.12.40, 10.3.26, 11.3.12
Safe to downgrade to: a release before 7.1.0
1. Check installed version
apt-cache policy jira-data-center || rpm -q jira-data-center || jira-data-center --version
2. UPGRADE to 9.12.40 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade jira-data-center
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade jira-data-center
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 7.1.0 (Debian / Ubuntu)
apt-cache madison jira-data-center
sudo apt install jira-data-center=<VERSION_BEFORE_7.1.0>
sudo apt-mark hold jira-data-center
3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list jira-data-center
sudo dnf downgrade jira-data-center-<VERSION_BEFORE_7.1.0>
sudo dnf versionlock add jira-data-center
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.
atlassian jira service desk UPGRADE
Affected: >= 3.1.0 and <= 4.13.27
Fixed in: newer than 4.13.27
Safe to downgrade to: a release before 3.1.0
1. Check installed version
apt-cache policy jira-service-desk || rpm -q jira-service-desk || jira-service-desk --version
2. UPGRADE to newer than 4.13.27 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade jira-service-desk
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade jira-service-desk
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 3.1.0 (Debian / Ubuntu)
apt-cache madison jira-service-desk
sudo apt install jira-service-desk=<VERSION_BEFORE_3.1.0>
sudo apt-mark hold jira-service-desk
3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list jira-service-desk
sudo dnf downgrade jira-service-desk-<VERSION_BEFORE_3.1.0>
sudo dnf versionlock add jira-service-desk
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.
Exact fixes by distribution
Fedora 46 · retext · FIXED · 8.1.0-1.fc46 · FEDORA-2026-0602a84203 · source
sudo dnf upgrade --advisory=FEDORA-2026-0602a84203
Public exploits and detection
Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.
- GitHub PoC: watchtowrlabs/watchTowr-vs-Atlassian-CVE-2026-21589 (15 stars)
- GitHub PoC: tc4dy/CVE-2026-21589-PoC-Exploit (11 stars)
- GitHub PoC: MarcusProgram/CVE-2026-21589 (9 stars)
- Nuclei scan template: Atlassian Jira/Confluence/Bitbucket - Pre-Auth Arbitrary File Read
Advisories and coverage
Official advisories
- Canadian Cyber Centre: Atlassian security advisory (AV26-1002) - Update 2 2026-10-15
Research and news
- Rapid7 Blog: CVE-2026-21589: Critical unauthenticated arbitrary file access in Atlassian products 2026-10-07
- watchTowr Labs: You Won’t Hear About These, Even In Myths (Atlassian Jira, Confluence (and more) Pre-Auth Arbitrary File Read CVE-2026-21589) 2026-10-06
Verify at the official source NVD · CVE Program · CISA KEV catalog · 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.
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.