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CVE-2021-26084

CRITICAL
9.8
CVSS Score
Published: August 30, 2021 at 06:30 AM UTC
Updated: June 17, 2026 at 03:42 AM UTC
2 products affected across 1 vendorConfluence ServerConfluence Data Center

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Severity
CRITICAL9.8
Exploitation
CISA KEV
Exploit prediction
EPSS 100%
SSVC
Active

Actively Exploited

CISA Known Exploited Vulnerabilities (KEV) Catalog

EPSS Score100.0%

EPSS (Exploit Prediction Scoring System) estimates a 100.0% chance this CVE is exploited in the wild within the next 30 days — higher than 100% of all CVEs. It complements CVSS: a high EPSS on a mid-severity CVE can still be urgent.

Atlassian Confluence Server and Data Server contain an Object-Graph Navigation Language (OGNL) injection vulnerability that may allow an unauthenticated attacker to execute code.

Required Action
Apply updates per vendor instructions.
Ransomware Use
Known
Added to KEV
Nov 3, 2021
Remediation Due
Nov 17, 2021
1810 days overdue
Notes
https://nvd.nist.gov/vuln/detail/CVE-2021-26084

Description

In affected versions of Confluence Server and Data Center, an OGNL injection vulnerability exists that would allow an unauthenticated attacker to execute arbitrary code on a Confluence Server or Data Center instance. The affected versions are before version 6.13.23, from version 6.14.0 before 7.4.11, from version 7.5.0 before 7.11.6, and from version 7.12.0 before 7.12.5.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Confluence Data Center· Atlassianatlassian-app
95%
v ≥ 6.14.0v ≥ 7.12.0v ≥ 7.5.0v < 6.13.23v < 7.11.6v < 7.12.5v < 7.4.116.14.0 ≤ v < 7.4.117.12.0 ≤ v < 7.12.57.5.0 ≤ v < 7.11.66.14.07.12.07.5.0
Affected range stops below 6.13.23, so it looks safe — our inference, not a vendor statement
Affected range stops below 7.11.6, so it looks safe — our inference, not a vendor statement
Affected range stops below 7.12.5, so it looks safe — our inference, not a vendor statement
Affected range stops below 7.4.11, so it looks safe — our inference, not a vendor statement
Confluence Server· Atlassianatlassian-app
95%
v ≥ 6.14.0v ≥ 7.12.0v ≥ 7.5.0v < 6.13.23v < 7.11.6v < 7.12.5v < 7.4.116.14.0 ≤ v < 7.4.117.12.0 ≤ v < 7.12.57.5.0 ≤ v < 7.11.66.14.07.12.07.5.0
Affected range stops below 6.13.23, so it looks safe — our inference, not a vendor statement
Affected range stops below 7.11.6, so it looks safe — our inference, not a vendor statement
Affected range stops below 7.12.5, so it looks safe — our inference, not a vendor statement
Affected range stops below 7.4.11, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

References (3)

x_refsource_MISCExploitThird Party AdvisoryVDB Entry
Source: [email protected]
http://packetstormsecurity.com/files/167449/Atlassian-Confluence-Namespace-OGNL-Injection.html
x_refsource_MISCIssue TrackingPatchVendor Advisory
Source: [email protected]
https://jira.atlassian.com/browse/CONFSERVER-67940
US Government Resource
Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-26084

SSVC — Action Prioritization

SSVCActiveAutomatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

9.8CRITICALCISA-ADP
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-917

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