CyberSecBulletin
CVE-2022-26134Exploited in the wildNVD status: Analyzed

Atlassian Confluence Server and Data Center Remote Code Execution

Published Updated By the CyberSecBulletin desk

CVE-2022-26134 is a critical-severity improper neutralization of special elements used in an expression language statement vulnerability in Confluence Data Center from Atlassian, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists versions 7.4.17, 7.13.7, 7.14.3 as the first without the flaw, so updating Confluence Data Center to one of those releases or later removes the exposure. CISA added it to the Known Exploited Vulnerabilities catalogue on June 2, 2022, which means attacks have been observed in the wild, including in ransomware campaigns.

Patch now

Attackers are already exploiting this vulnerability, according to CISA.

What to do

  1. Update Confluence Data Center to 7.4.17 or 7.13.7 or 7.14.3 or 7.15.2, whichever matches your release line, or a later version.
  2. Update Confluence Server to 7.4.17 or 7.13.7 or 7.14.3 or 7.15.2, whichever matches your release line, or a later version.
  3. CISA's required action: Immediately block all internet traffic to and from affected products AND apply the update per vendor instructions [https://confluence.atlassian.com/doc/confluence-security-advisory-2022-06-02-1130377146.html] OR remove the affected products by the due date on the right. Note: Once the update is successfully deployed, agencies can reassess the internet blocking rules.
  4. Read the advisory on confluence.atlassian.com for workarounds and exact fixed builds.
  5. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
AtlassianConfluence Data Centernext of 1.3.0; before 7.4.17; 7.13.0; before 7.13.7; 7.14.0; before 7.14.3; 7.15.0; before 7.15.2; and 6 more ranges7.4.17, 7.13.7, 7.14.3, 7.15.2, 7.16.4, 7.17.4
AtlassianConfluence Servernext of 1.3.0; before 7.4.17; 7.13.0; before 7.13.7; 7.14.0; before 7.14.3; 7.15.0; before 7.15.2; and 6 more ranges7.4.17, 7.13.7, 7.14.3, 7.15.2, 7.16.4, 7.17.4

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.19.8CriticalNVD
CVSS 3.19.8CriticalCISA (ADP)
CVSS 2.07.5HighNVD

Official 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 from 1.3.0 before 7.4.17, from 7.13.0 before 7.13.7, from 7.14.0 before 7.14.3, from 7.15.0 before 7.15.2, from 7.16.0 before 7.16.4, from 7.17.0 before 7.17.4, and from 7.18.0 before 7.18.1.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Improper Neutralization of Special Elements used in an Expression Language Statement

The product constructs all or part of an expression language (EL) statement in a framework such as a Java Server Page (JSP) using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended EL statement before it is executed.

How developers prevent this class of flaw

  • Avoid adding user-controlled data into an expression interpreter when possible.
  • If user-controlled data must be added to an expression interpreter, one or more of the following should be performed: Validate that the user input will not evaluate as an expression Encode the user input in a way that ensures it is not evaluated as an expression
  • The framework or tooling might allow the developer to disable or deactivate the processing of EL expressions, such as setting the isELIgnored attribute for a JSP page to true.

More Improper Neutralization of Special Elements used in an Expression Language Statement vulnerabilities (CWE-917)

Timeline

  1. Added to CISA's Known Exploited Vulnerabilities catalogue.
  2. CVE record published.
  3. Deadline for US federal agencies to remediate, set by CISA.
  4. CISA published its SSVC assessment (exploitation: active, automatable: yes, technical impact: total).
  5. Record last changed materially (score, affected products, status or references).

References

Technical write-ups (may include proof of concept)

Other vulnerabilities in Confluence Data Center

All Confluence Data Center vulnerabilities

Recent Improper Neutralization of Special Elements used in an Expression Language Statement vulnerabilities

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