CVE-2016-6798
XML External Entity Reference in Apache Sling
CVE-2016-6798 is a critical vulnerability (CVSS 9.8) in Apache Sling, published July 19, 2017. Public exploit code exists. EPSS puts the chance of exploitation in the next 30 days at 3.67%, the 89th percentile. Fixed in org.apache.sling:org.apache.sling.xss 1.0.12.
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
NVD Score used
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.
- Record
CVE-2016-6798- CVSS 3.0
- 9.8 Critical
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - CVSS 2.0
- 7.5 High
AV:N/AC:L/Au:N/C:P/I:P/A:P - Weakness
- CWE-611
- Updated
- 2026-11-02
CVE List No score
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.
- Record
CVE-2016-6798- Updated
- 2026-11-02
EUVDEUVD-2022-2991 No score
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.
- Record
EUVD-2022-2991- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-7g54-vgp6-jj5w
XML External Entity Reference in Apache Sling
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.
- Record
GHSA-7g54-vgp6-jj5w- CVSS 3.0
- 9.8 Critical
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-611
- Updated
- 2026-11-02
OSVGHSA-7g54-vgp6-jj5w
XML External Entity Reference in Apache Sling
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.
- Record
GHSA-7g54-vgp6-jj5w- CVSS 3.0
- 9.8 Critical
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-611
- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
org.apache.sling:org.apache.sling.xssMaven |
before 1.0.12 | 1.0.12 |
org.apache.sling:org.apache.sling.xss.compatMaven |
before 1.1.0 | 1.1.0 |
org.apache.sling:org.apache.sling.xssMaven |
before 1.0.12, plus listed versions 1.0.01.0.21.0.41.0.61.0.8 |
1.0.12 |
org.apache.sling:org.apache.sling.xss.compatMaven |
before 1.1.0, plus listed versions 1.0.0 |
1.1.0 |
Public exploits
Links only. Every CVE stores no exploit code.
| Source | Link | Date |
|---|---|---|
| PoC in GitHub | tafamace/CVE-2016-6798 | 2018-11-19 |
History
| When | Changed | Sources |
|---|---|---|
| 2026-11-03 | aliases | EUVD |
| 2026-11-02 | created | CVE List, GitHub Advisories, NVD, OSV, PoC in GitHub |
References
lists.apache.org/thread.html/b72c3a511592ec70729b3ec2d29302b6ce87bbeab62d4745617a6bd0%40%3Cdev.sling.apache.org%3E
securityfocus.com/bid/99873
nvd.nist.gov/vuln/detail/CVE-2016-6798
github.com/apache/sling-org-apache-sling-xss/commit/de32b144ad2be3367559f6184d560db42a220529