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XSS in Action View

Moderate severity GitHub Reviewed Published Sep 11, 2020 in rails/rails • Updated May 4, 2023

Package

bundler actionview (RubyGems)

Affected versions

>= 6.0.0.0, <= 6.0.3.2
<= 5.2.4.3

Patched versions

6.0.3.3
5.2.4.4

Description

There is a potential Cross-Site Scripting (XSS) vulnerability in Action View's translation helpers. Views that allow the user to control the default (not found) value of the t and translate helpers could be susceptible to XSS attacks.

Impact

When an HTML-unsafe string is passed as the default for a missing translation key named html or ending in _html, the default string is incorrectly marked as HTML-safe and not escaped. Vulnerable code may look like the following examples:

<%# The welcome_html translation is not defined for the current locale: %>
<%= t("welcome_html", default: untrusted_user_controlled_string) %>

<%# Neither the title.html translation nor the missing.html translation is defined for the current locale: %>
<%= t("title.html", default: [:"missing.html", untrusted_user_controlled_string]) %>

Patches

Patched Rails versions, 6.0.3.3 and 5.2.4.4, are available from the normal locations.

The patches have also been applied to the master, 6-0-stable, and 5-2-stable branches on GitHub. If you track any of these branches, you should update to the latest.

To aid users who aren’t able to upgrade immediately, we’ve provided patches for the two supported release series. They are in git-am format and consist of a single changeset.

Please note that only the 5.2 and 6.0 release series are currently supported. Users of earlier, unsupported releases are advised to update as soon as possible, as we cannot provide security fixes for unsupported releases.

Workarounds

Impacted users who can’t upgrade to a patched Rails version can avoid this issue by manually escaping default translations with the html_escape helper (aliased as h):

<%= t("welcome_html", default: h(untrusted_user_controlled_string)) %>

References

@georgeclaghorn georgeclaghorn published to rails/rails Sep 11, 2020
Reviewed Sep 11, 2020
Published to the GitHub Advisory Database Sep 11, 2020
Last updated May 4, 2023

Severity

Moderate
5.4
/ 10

CVSS base metrics

Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N

Weaknesses

CVE ID

CVE-2020-15169

GHSA ID

GHSA-cfjv-5498-mph5

Source code

Credits

Checking history
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