Redmine before 4.2.11 and 5.0.x before 5.0.6 allows XSS via thumbnails.

Redmine before 4.2.11 and 5.0.x before 5.0.6 allows XSS in the Textile formatter.

Redmine before 4.2.11 and 5.0.x before 5.0.6 allows XSS in a Markdown formatter.

Redmine before 4.2.9 and 5.0.x before 5.0.4 allows persistent XSS in its Textile formatter due to improper sanitization in Redcloth3 Textile-formatted fields. Depending on the configuration, this may require login as a registered user.

Redmine before 4.2.9 and 5.0.x before 5.0.4 allows persistent XSS in its Textile formatter due to improper sanitization of the blockquote syntax in Textile-formatted fields.

Redmine before 4.1.5 and 4.2.x before 4.2.3 may disclose the names of users on activity views due to an insufficient access filter.

Redmine before 4.0.9 and 4.1.x before 4.1.3 allows an attacker to learn the values of internal authentication keys by observing timing differences in string comparison operations within SysController and MailHandlerController.

Redmine before 4.0.9, 4.1.x before 4.1.3, and 4.2.x before 4.2.1 allows users to circumvent the allowed filename extensions of uploaded attachments.

Redmine before 4.0.9, 4.1.x before 4.1.3, and 4.2.x before 4.2.1 allows attackers to bypass the add_issue_notes permission requirement by leveraging the incoming mail handler.

Insufficient input validation in the Git repository integration of Redmine before 4.0.9, 4.1.x before 4.1.3, and 4.2.x before 4.2.1 allows Redmine users to read arbitrary local files accessible by the application server process.

Redmine before 4.0.8 and 4.1.x before 4.1.2 allows attackers to bypass the add_issue_notes permission requirement by leveraging the Issues API.

Redmine before 4.0.8 and 4.1.x before 4.1.2 allows attackers to discover the names of private projects if issue-journal details exist that have changes to project_id values.

Redmine before 4.0.7 and 4.1.x before 4.1.1 allows attackers to discover the subject of a non-visible issue by performing a CSV export and reading time entries.

Redmine before 4.0.7 and 4.1.x before 4.1.1 has stored XSS via textile inline links.

Redmine before 4.0.7 and 4.1.x before 4.1.1 has XSS via the back_url field.

Redmine before 3.4.13 and 4.x before 4.0.6 mishandles markup data during Textile formatting.

In Redmine before 3.4.11 and 4.0.x before 4.0.4, persistent XSS exists due to textile formatting errors.

Redmine before 3.2.9, 3.3.x before 3.3.6, and 3.4.x before 3.4.4 does not block the --config and --debugger flags to the Mercurial hg program, which allows remote attackers to execute arbitrary commands (through the Mercurial adapter) via vectors involving a branch whose name begins with a --config= or --debugger= substring, a related issue to CVE-2017-17536.

In Redmine before 3.2.8, 3.3.x before 3.3.5, and 3.4.x before 3.4.3, XSS exists in app/views/issues/_list.html.erb via crafted column data.

In Redmine before 3.2.8, 3.3.x before 3.3.5, and 3.4.x before 3.4.3, XSS exists in app/views/timelog/_list.html.erb via crafted column data.