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XML External Entity Reference in Apache Sling

Critical severity GitHub Reviewed Published May 17, 2022 to the GitHub Advisory Database • Updated Oct 11, 2023

Package

maven org.apache.sling:org.apache.sling.xss (Maven)

Affected versions

< 1.0.12

Patched versions

1.0.12
maven org.apache.sling:org.apache.sling.xss.compat (Maven)
< 1.1.0
1.1.0

Description

In the XSS Protection API module before 1.0.12 in Apache Sling, the method XSS.getValidXML() uses an insecure SAX parser to validate the input string, which allows for XXE attacks in all scripts which use this method to validate user input, potentially allowing an attacker to read sensitive data on the filesystem, perform same-site-request-forgery (SSRF), port-scanning behind the firewall or DoS the application.

References

Published by the National Vulnerability Database Jul 19, 2017
Published to the GitHub Advisory Database May 17, 2022
Reviewed Nov 3, 2022
Last updated Oct 11, 2023

Severity

Critical

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS score

0.096%
(41st percentile)

Weaknesses

CVE ID

CVE-2016-6798

GHSA ID

GHSA-7g54-vgp6-jj5w

Source code

No known source code

Credits

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