Summary
Reflected Cross-site Scripting in ACS Commons
This issue has been resolved in v4.10.0
Workarounds
No workaround exist.
References
N/A
For more information
If you have any questions or comments about this advisory open an issue in acs-aem-commons.
Credit
This issue was discovered and reported by Christopher Whipp ([email protected]).
Impact
ACS Commons version 4.9.2 (and earlier) suffers from a Reflected Cross-site Scripting (XSS) vulnerability in version-compare and page-compare due to invalid JCR characters that are not handled correctly.
An attacker could potentially exploit this vulnerability to inject malicious JavaScript content into vulnerable form fields and execute it within the context of the victim's browser. Exploitation of this issue requires user interaction in order to be successful.
Untrusted input is rendered as active markup in a victim's browser, which can run script in their session. Typical impact: session or credential theft, and actions taken as the user.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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See it in your environmentNew to Kodem? Get a demo →Remediation advice
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2021-21028? CVE-2021-21028 is a high-severity cross-site scripting (XSS) vulnerability in com.adobe.acs:acs-aem-commons (maven), affecting versions < 4.10.0. It is fixed in 4.10.0. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
- Which versions of com.adobe.acs:acs-aem-commons are affected by CVE-2021-21028? com.adobe.acs:acs-aem-commons (maven) versions < 4.10.0 is affected.
- Is there a fix for CVE-2021-21028? Yes. CVE-2021-21028 is fixed in 4.10.0. Upgrade to this version or later.
- Is CVE-2021-21028 exploitable, and should I be worried? Whether CVE-2021-21028 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2021-21028 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2021-21028? Upgrade
com.adobe.acs:acs-aem-commonsto 4.10.0 or later.