CVE-2026-21589 — Atlassian Multiple Products Files or Directories Accessible to External Parties Vulnerability
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 vulnerability does not allow attackers to enumerate or list directory contents. In some configurations, there may be some sensitive files that make this highly severe. This vulnerability allows an unauthenticated remote attacker to access specific files within the web application root directory in affected versions. The vulnerability must be addressed for affected versions of: -- Bitbucket Data Center, introduced in version >= 4.6.0, fix versions: 9.4.26, 10.2.8, 10.5.1 -- Confluence Data Center, introduced in version >= 5.10.0, fix versions 9.2.26, 10.2.19 -- Crowd Data Center, introduced in version >= 2.11.0, fix versions 6.3.7, 7.0.3, 7.1.7, 7.2.4 -- Jira Software Data Center, introduced in version >= 7.1.0, fix versions 9.12.40, 10.3.26, 11.3.12 -- Jira Service Management Data Center, introduced in version >= 3.1.0, fix versions 5.12.40, 10.3.26, 11.3.12 -- Bamboo Data Center >= 7.0.1, fix versions 10.2.24, 12.1.12 -- Crucible, fix versions 4.9.15 -- Fisheye, fix version 4.9.15 -- Exploitation requires prior knowledge of the target file's exact name and path. The vulnerability does not include the capability to enumerate or list directory contents.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- Confirmed exploitation (CISA KEV)+35
- Public exploit/PoC (nuclei, github)+10
- EPSS 2.8% (30-day exploitation probability)+13
- Technical severity (high)+6
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
CISA SSVC assessment CISA
Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
- Documented mitigation — jira.atlassian.com (NIST National Vulnerability Database)
- Documented mitigation — jira.atlassian.com (NIST National Vulnerability Database)
- Documented mitigation — jira.atlassian.com (NIST National Vulnerability Database)
- Documented mitigation — jira.atlassian.com (NIST National Vulnerability Database)
- Documented mitigation — jira.atlassian.com (NIST National Vulnerability Database)
- Documented mitigation — jira.atlassian.com (NIST National Vulnerability Database)
- Documented mitigation — jira.atlassian.com (NIST National Vulnerability Database)
- Documented mitigation — jira.atlassian.com (NIST National Vulnerability Database)
CISA required action CISA
Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
US federal deadline: Oct 18, 2026 — due in 3 day(s)
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Atlassian Bamboo, Atlassian Bamboo Data Center, Atlassian Bitbucket Data Center…).
- Treat as emergency remediation: the CVE is in CISA KEV (confirmed exploitation).
- The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
- Apply the documented mitigations until a definitive fix is available.
- Search available logs for exploit probes matching the vulnerability class (access control), errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Atlassian | Bamboo | ≥ 11.0.0 and < 12.1.12≥ 7.0.1 and < 10.2.24 | Vulnerable | NIST National Vulnerability Database |
| Atlassian | Bamboo Data Center | version All other versions | Vulnerable | CVE Program (cve.org) e CISA ADP |
| Atlassian | Bitbucket Data Center | version All other versions | Vulnerable | CVE Program (cve.org) e CISA ADP |
| Atlassian | Bitbucket Data Center | ≥ 7.17.0 and < 9.4.26≥ 9.5.0 and < 10.2.8≥ 10.3.0 and < 10.5.1 | Vulnerable | NIST National Vulnerability Database |
| Atlassian | Bitbucket Server | ≥ 4.6.0 and ≤ 8.14.6 | Vulnerable | NIST National Vulnerability Database |
| Atlassian | Confluence Data Center | ≥ 5.10.0 and < 9.2.26≥ 9.3.0 and < 10.2.19 | Vulnerable | NIST National Vulnerability Database |
| Atlassian | Confluence Data Center | version All other versions | Vulnerable | CVE Program (cve.org) e CISA ADP |
| Atlassian | Crowd | ≥ 7.2.0 and < 7.2.4≥ 7.1.0 and < 7.1.7≥ 7.0.0 and < 7.0.3≥ 2.11.0 and < 6.3.7 | Vulnerable | NIST National Vulnerability Database |
| Atlassian | Crowd Data Center | version All other versions | Vulnerable | CVE Program (cve.org) e CISA ADP |
| Atlassian | Crucible | < 4.9.15 | Vulnerable | NIST National Vulnerability Database |
| Atlassian | Crucible Data Center | version All other versions | Vulnerable | CVE Program (cve.org) e CISA ADP |
| Atlassian | Fisheye | < 4.9.15 | Vulnerable | NIST National Vulnerability Database |
| Atlassian | Fisheye Data Center | version All other versions | Vulnerable | CVE Program (cve.org) e CISA ADP |
| Atlassian | Jira Data Center | ≥ 10.4.0 and < 11.3.12≥ 9.13.0 and < 10.3.26≥ 7.1.0 and < 9.12.40 | Vulnerable | NIST National Vulnerability Database |
| Atlassian | Jira Service Management | ≥ 3.1.0 and < 5.12.40≥ 5.13.0 and < 10.3.26≥ 10.4.0 and < 11.3.12 | Vulnerable | NIST National Vulnerability Database |
| Atlassian | Jira Service Management Data Center | version All other versions | Vulnerable | CVE Program (cve.org) e CISA ADP |
| Atlassian | Jira Software Data Center | version All other versions | Vulnerable | CVE Program (cve.org) e CISA ADP |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 9.3 | CVSS 4.0 | Critical | — | — | security@atlassian.com via NIST National Vulnerability Database |
| 9.3 | CVSS 4.0 | Critical | — | — | atlassian via CVE Program (cve.org) e CISA ADP |
| 7.5 | CVSS 3.1 | High | 3.9 | 3.6 | nvd@nist.gov via NIST National Vulnerability Database |
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N (score shown at the top: nvd@nist.gov) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
CWE-552 · Files or Directories Accessible to External Parties
CISA KEV details CISA
CISA lists a CVE once it has evidence of exploitation against real targets.
CISA records ransomware use only for campaigns it has confirmed, so “Unknown” means unrecorded, not ruled out. The deadline binds US federal agencies; for everyone else it is a reference date.
Public exploits, PoCs and detection templates
Public code that demonstrates or tests the flaw raises the odds of mass exploitation — and Nuclei templates help find vulnerable assets in your environment.
- watchtowrlabs/watchTowr-vs-Atlassian-CVE-2026-21589 ★ 14 Oct 6, 2026
- MarcusProgram/CVE-2026-21589 ★ 10 Oct 6, 2026
- CVE-2026-21589 - Atlassian Data Center Unauth Arbitrary File Read (CVSS 9.3). Red/Blue Team suite with 2 tools: Full Exploit (path traversal, WEB-INF read, interactive shell, 8 products, mass scan, SOCKS5/Tor, stealth) and SafeChecker (non-intrusive version audit, WAF detection, IoC guidance, JSON/C ★ 10 Oct 6, 2026
- CVE-2026-21589 detector for Atlassian Data Center webresource traversal. Pre-auth webroot file read confirm for Jira, Confluence and Bitbucket. ★ 8 Oct 7, 2026
- CVE-2026-21589 — Atlassian DC pre-auth arbitrary file read (CVSS 4.0 9.3). PoCbit PoC: atlassian-plugins-webresource ..:: traversal on /download/resources/ for Jira, Confluence, Bitbucket. check + exploit (WEB-INF/web.xml, crowd.properties). Batch JSONL, hits.txt. Not RCE. https://pocbit.org/pocs/cv ★ 1 Oct 8, 2026
- Atlassian Arbitrary File Read ★ 1 Oct 9, 2026
- Atlassian Arbitrary File Read ★ 0 Oct 7, 2026
- BimBoxH4/CVE-2026-21589 ★ 0 Oct 7, 2026
- CVE-2026-21589 ★ 0 Oct 7, 2026
- CVE-2026-21589 is a critical (CVSS 9.3) arbitrary file access vulnerability affecting all versions of eight Atlassian Data Center products, including Jira, Confluence, Bitbucket, Bamboo, Crowd, Crucible, Fisheye, and Jira Service Management. ★ 0 Oct 8, 2026
Warning: public PoCs are sometimes disguised malware. Use them only for authorized testing in an isolated environment. This portal does not host exploit code — it only points to the sources.
EPSS over time FIRST
Oct 13, 2026 → Oct 15, 2026 · 3 reading(s) · max 2.78%
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
- Audit administrative actions and access to resources outside each user’s normal pattern.
- Hunt retroactively in logs from before Oct 15, 2026 (KEV listing): exploitation may have started earlier.
Timeline
What happened to this CVE, newest first.
- 2026
- Fix documented
- Affected products added · atlassian/bitbucket data center, atlassian/bitbucket server, atlassian/confluence data center, atlassian/crowd, atlassia
- CVSS changed · 9.3 → 7.5
- Source status changed · Awaiting Analysis → Analyzed
- Added to CISA KEV (detected)
- SSVC assessment updated
- Added to CISA KEV catalog
- Affected products added · atlassian/bamboo data center, atlassian/bitbucket data center, atlassian/confluence data center, atlassian/crowd data ce
- SSVC assessment updated
- Record published
- CVSS changed · 9.3
- Source status changed · → Awaiting Analysis
- Record created in this database
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 2× References added · Oct 14, 2026 – Oct 15, 2026
- 1× Official description updated · Oct 13, 2026 – Oct 13, 2026
References
12 on the record
- jira.atlassian.com/browse/BSERV-20604
- jira.atlassian.com/browse/FE-7583
- jira.atlassian.com/browse/CRUC-8741
- jira.atlassian.com/browse/BAM-26567
- jira.atlassian.com/browse/CONFSERVER-104488
- jira.atlassian.com/browse/CWD-6610
- jira.atlassian.com/browse/JRASERVER-79546
- jira.atlassian.com/browse/JSDSERVER-16809
- www.cisa.gov/known-exploited-vulnerabilities-catalog
- github.com/watchtowrlabs/watchTowr-vs-Atlassian-CVE-2026-21589
- nvd.nist.gov/vuln/detail/CVE-2026-21589
- github.com/advisories/GHSA-gr66-x5pq-8g2g
Elsewhere on this site
Related CVEs (same products)
- High CVE-2026-21586 Improper Authorization in Atlassian Confluence Data Center Sep 15, 2026
- High CVE-2026-21582 Improper Authentication in Atlassian Crowd Data Center Aug 18, 2026
- High CVE-2026-21584 Improper Authorization in Atlassian Bamboo Aug 18, 2026
- High CVE-2026-21579 Exposure of Sensitive Information in Atlassian Confluence Data Center Jul 21, 2026
- Medium CVE-2026-21577 Uncontrolled Resource Consumption in Atlassian Confluence Data Center Jul 21, 2026
- High CVE-2026-21571 OS Command Injection in Atlassian Bamboo Apr 21, 2026
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2026-21589 is "Atlassian Multiple Products Files or Directories Accessible to External Parties Vulnerability", rated High. It affects Bamboo (Atlassian); versions are in the scope table. It is in CISA KEV: there is evidence of real-world exploitation. CVSS 7.5 describes technical severity. EPSS 2.78% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
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