Package Instance

Cross-site Scripting vulnerability in Jenkins
Since Jenkins 2.340, the tooltip of the build button in list views supports HTML without escaping the job display name.

This vulnerability is known to be exploitable by attackers with Job/Configure permission.

Jenkins 2.356 addresses this vulnerability. The tooltip of the build button in list views is now escaped.

No Jenkins LTS release is affected by SECURITY-2776 or SECURITY-2780, as these were not present in Jenkins 2.332.x and fixed in the 2.346.x line before 2.346.1.

Unauthorized view fragment access in Jenkins
Jenkins uses the Stapler web framework to render its UI views. These views are frequently composed of several view fragments, enabling plugins to extend existing views with more content.

Before [SECURITY-534](https://www.jenkins.io/security/advisory/2019-07-17/#SECURITY-534) was fixed in Jenkins 2.186 and LTS 2.176.2, attackers could in some cases directly access a view fragment containing sensitive information, bypassing any permission checks in the corresponding view.

In Jenkins 2.335 through 2.355 (both inclusive), the protection added for SECURITY-534 is disabled for some views. As a result, attackers could in very limited cases directly access a view fragment containing sensitive information, bypassing any permission checks in the corresponding view.

As of publication, the Jenkins security team is unaware of any vulnerable view fragment across the Jenkins plugin ecosystem.

Jenkins 2.356 restores the protection for affected views.

No Jenkins LTS release is affected by this issue, as it was not present in Jenkins 2.332.x and fixed in the 2.346.x line before 2.346.1.

Cross-site Scripting vulnerability in Jenkins
Since Jenkins 2.320 and LTS 2.332.1, help icon tooltips no longer escape the feature name, effectively undoing the fix for [SECURITY-1955](https://www.jenkins.io/security/advisory/2020-08-12/#SECURITY-1955).

This vulnerability is known to be exploitable by attackers with Job/Configure permission.

Jenkins 2.356, LTS 2.332.4 and LTS 2.346.1 addresses this vulnerability, the feature name in help icon tooltips is now escaped.

Cross-site Scripting vulnerability in Jenkins
Since Jenkins 2.321 and LTS 2.332.1, the HTML output generated for new symbol-based SVG icons includes the `title` attribute of `l:ionicon` until Jenkins 2.334 and `alt` attribute of `l:icon` since Jenkins 2.335 without further escaping.

This vulnerability is known to be exploitable by attackers with Job/Configure permission.

Jenkins 2.356, LTS 2.332.4 and LTS 2.346.1 addresses this vulnerability, the `title` attribute of `l:ionicon` (Jenkins LTS 2.332.4) and `alt` attribute of `l:icon` (Jenkins 2.356 and LTS 2.346.1) are escaped in the generated HTML output.

Cross-site Scripting vulnerability in Jenkins
Since Jenkins 2.340, symbol-based icons unescape previously escaped values of `tooltip` parameters.

This vulnerability is known to be exploitable by attackers with Job/Configure permission.

Jenkins 2.356, LTS 2.332.4 and LTS 2.346.1 addresses this vulnerability. Symbol-based icons no longer unescape values of `tooltip` parameters.

Observable timing discrepancy allows determining username validity in Jenkins
In Jenkins 2.355 and earlier, LTS 2.332.3 and earlier, an observable timing discrepancy on the login form allows distinguishing between login attempts with an invalid username, and login attempts with a valid username and wrong password, when using the Jenkins user database security realm. This allows attackers to determine the validity of attacker-specified usernames.

Login attempts with an invalid username now validate a synthetic password to eliminate the timing discrepancy in Jenkins 2.356, LTS 2.332.4.