Summary
Stored XSS in TimelineJS3
Workarounds
To exploit this vulnerability, the attacker must have write access to the data source for the Timeline or the server which embeds the timeline.
Thus, the only workaround is appropriate attention to securing write access to the Google Sheet or JSON file which serves as the data source.
References
For more about the release of TimelineJS which addresses this vulnerability, see the Knight Lab website.
A technical write-up of this vulnerability is available here.
Acknowledgements
This vulnerability was discovered by Zander Work (@captainGeech42) of Oregon State University.
For more information
If you have any questions or comments about this advisory:
- Open an issue in GitHub
- File a support request in our helpdesk system
Impact
TimelineJS renders some user data as HTML. An attacker could implement an XSS exploit with maliciously crafted content in a number of data fields. This risk is present whether the source data for the timeline is stored on Google Sheets or in a JSON configuration file.
Most TimelineJS users configure their timeline with a Google Sheets document. Those users are exposed to this vulnerability if they grant write access to the document to a malicious inside attacker, if the access of a trusted user is compromised, or if they grant public write access to the document.
Some TimelineJS users configure their timeline with a JSON document. Those users are exposed to this vulnerability if they grant write access to the document to a malicious inside attacker, if the access of a trusted user is compromised, or if write access to the system hosting that document is otherwise compromised.
Although the vulnerability has a CVSS v3.1 base score of 7.2, this vulnerability has a severity of Moderate due to the likeliness of exploitation.
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-2020-15092 has a CVSS score of 7.2 (High). The vector is network-reachable, high privileges required, and no user interaction. 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 (3.7.0); 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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See it in your environmentNew to Kodem? Get a demo →Remediation advice
Version 3.7.0 of TimelineJS addresses this in two ways.
- For content which is intended to support limited HTML markup for styling and linking, that content is "sanitized" before being added to the DOM.
- For content intended for simple text display, all markup is stripped.
Very few users of TimelineJS actually install the TimelineJS code on their server. Most users publish a timeline using a URL hosted on systems we control. The fix for this issue is published to our system such that those users will automatically begin using the new code. The only exception would be users who have deliberately edited the embed URL to "pin" their timeline to an earlier version of the code.
Some users of TimelineJS use it as a part of a wordpress plugin. Version 3.7.0.0 of that plugin and newer integrate the updated code. Users are encouraged to update the plugin rather than manually update the embedded version of TimelineJS.
Frequently Asked Questions
- What is CVE-2020-15092? CVE-2020-15092 is a high-severity cross-site scripting (XSS) vulnerability in @knight-lab/timelinejs (npm), affecting versions < 3.7.0. It is fixed in 3.7.0. Untrusted input is rendered as active markup in a victim's browser, which can run script in their session.
- How severe is CVE-2020-15092? CVE-2020-15092 has a CVSS score of 7.2 (High). 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 @knight-lab/timelinejs are affected by CVE-2020-15092? @knight-lab/timelinejs (npm) versions < 3.7.0 is affected.
- Is there a fix for CVE-2020-15092? Yes. CVE-2020-15092 is fixed in 3.7.0. Upgrade to this version or later.
- Is CVE-2020-15092 exploitable, and should I be worried? Whether CVE-2020-15092 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-2020-15092 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-2020-15092? Upgrade
@knight-lab/timelinejsto 3.7.0 or later.