CVE-2021-21610 Reflected XSS vulnerability in Jenkins markup formatter preview
Reflected XSS in Jenkins allows attackers to execute scripts if the markup formatter permits unsafe elements, potentially leading to session hijacking or code execution.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2021-21610?
CVE-2021-21610 is a medium-severity cross-site scripting vulnerability in Jenkins Jenkins, published on 13 Jan 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
Jenkins 2.274 and earlier, LTS 2.263.1 and earlier does not implement any restrictions for the URL rendering a formatted preview of markup passed as a query parameter, resulting in a reflected cross-site scripting (XSS) vulnerability if the configured markup formatter does not prohibit unsafe elements (JavaScript) in markup.
Weakness: CWE-79
Which versions are affected by CVE-2021-21610?
5 open source packages ship an affected version, including org.jenkins-ci.main:jenkins-core and jenkins. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
org.jenkins-ci.main:jenkins-core Maven | All versions | 2.263.2 |
org.jenkins-ci.main:jenkins-core Maven | All versions | 2.263.2 |
org.jenkins-ci.main:jenkins-core Maven | From 2.264 | 2.275 |
org.jenkins-ci.main:jenkins-core Maven | From 2.264 | 2.275 |
jenkins Bitnami | All versions | 2.274.1 |
Products include Jenkins Jenkins.
How do I fix CVE-2021-21610?
Upgrade org.jenkins-ci.main:jenkins-core to a fixed version for your release line: 2.263.2 or 2.275.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2021-21610 being exploited?
There is no known exploitation of CVE-2021-21610 in the wild and no public exploit code.
Other vulnerabilities in Jenkins Jenkins
- CVE-2024-23897 Jenkins Command Line Interface (CLI) Path Traversal
- CVE-2018-1000861 Jenkins Stapler Web Framework Deserialization of Untrusted Data
- CVE-2017-1000353 Jenkins Remote Code Execution
- CVE-2015-5317 Jenkins User Interface (UI) Information Disclosure
- CVE-2021-21690 Multiple vulnerabilities allow bypassing path filtering of agent-to-controller access control in Jenkins
Sources
Also known as BIT-jenkins-2021-21610, GHSA-7qf3-c2q8-69m3.