Summary
Cross-site scripting in SimpleSAMLphp
Background
SimpleSAMLphp allows users to report errors and failures to the system administrators via a web form. This web form gathers some contextual information automatically, but it also allows the user to provide their email address for follow-ups and a free-text explanation of what happened. Once submitted, the report is sent as an email to the administrative email address configured in the software.
Description
The www/erroreport.php script allows error reports to be submitted and sent to the system administrator. Starting with SimpleSAMLphp 1.18.0, a new SimpleSAML\Utils\EMail class was introduced to handle sending emails, implemented as a wrapper of an external dependency.
This new wrapper allows us to use Twig templates in order to create the email sent with an error report. Since Twig provides automatic escaping of variables, manual escaping of the free-text field in www/errorreport.php was removed to avoid double escaping. However, for those not using the new user interface yet, an email template is hardcoded into the class itself in plain PHP. Since no escaping is provided in this template, it is then possible to inject HTML inside the template by manually crafting the contents of the free-text field.
Affected versions
SimpleSAMLphp versions 1.18.0 to 1.18.3, both inclusive.
Resolution
Upgrade the SimpleSAMLphp installation to version 1.18.4.
Credit
This vulnerability was discovered and reported by Frederic Vleminckx.
Impact
An attacker may take advantage of this issue to manually craft a modified email sent via the error reporting mechanism, such as this email might trick a system administrator into performing an action, such as introducing their credentials into a phishing web site that resembles the original.
Remote execution of javascript code is considered unfeasible since email clients do not run javascript present in emails, although there might be email clients which don't follow this rule, making the attack surface grow.
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.
CVE-2020-5226 has a CVSS score of 4.4 (Low). The vector is network-reachable, low privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.18.4); upgrading removes the vulnerable code path.
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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Frequently Asked Questions
- What is CVE-2020-5226? CVE-2020-5226 is a low-severity cross-site scripting (XSS) vulnerability in simplesamlphp/simplesamlphp (composer), affecting versions >= 1.18.0, < 1.18.4. It is fixed in 1.18.4. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
- How severe is CVE-2020-5226? CVE-2020-5226 has a CVSS score of 4.4 (Low). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of simplesamlphp/simplesamlphp are affected by CVE-2020-5226? simplesamlphp/simplesamlphp (composer) versions >= 1.18.0, < 1.18.4 is affected.
- Is there a fix for CVE-2020-5226? Yes. CVE-2020-5226 is fixed in 1.18.4. Upgrade to this version or later.
- Is CVE-2020-5226 exploitable, and should I be worried? Whether CVE-2020-5226 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-2020-5226 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-2020-5226? Upgrade
simplesamlphp/simplesamlphpto 1.18.4 or later.