CVE-2021-32633 Remote Code Execution via traversal in TAL expressions

What is CVE-2021-32633?

CVE-2021-32633 is a medium-severity path traversal vulnerability in Plone Plone, published on 21 May 2021. Any signed-in user can exploit it over the network, with no action from the victim.

Official description

Zope is an open-source web application server. In Zope versions prior to 4.6 and 5.2, users can access untrusted modules indirectly through Python modules that are available for direct use. By default, only users with the Manager role can add or edit Zope Page Templates through the web, but sites that allow untrusted users to add/edit Zope Page Templates through the web are at risk from this vulnerability. The problem has been fixed in Zope 5.2 and 4.6. As a workaround, a site administrator can restrict adding/editing Zope Page Templates through the web using the standard Zope user/role permission mechanisms. Untrusted users should not be assigned the Zope Manager role and adding/editing Zope Page Templates through the web should be restricted to trusted users only.

Weakness: CWE-22

Which versions are affected by CVE-2021-32633?

9 open source packages ship an affected version, including zope and Zope. It affects 2 products.

Products include Plone Plone, Zope Zope.

How do I fix CVE-2021-32633?

Upgrade zope to a fixed version for your release line: 4.6 or 5.2.

Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.

Is CVE-2021-32633 being exploited?

There is no known exploitation of CVE-2021-32633 in the wild and no public exploit code.

Other vulnerabilities in Plone Plone

• CVE-2021-33509 Incorrect Permission Assignment for Critical Resource in Plone Critical 9.9
• CVE-2020-35190 Hardcoded credentials in n/a Critical 9.8
• CVE-2020-7941 Plone Unauthenticated Write Vulnerability Critical 9.8
• CVE-2011-3587 Zope Command Execution Vulnerability Critical 9.3
• CVE-2021-33926 Server-Side Request Forgery in Plone CMS High 8.8

All Plone Plone vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• GitHub advisory
• How this page is made

Also known as GHSA-5pr9-v234-jw36, GHSA-962m-m8jw-8wrr, PYSEC-2021-88.