CVE-2021-32674 Remote Code Execution via traversal in TAL expressions
Attackers with Manager role can execute arbitrary code via TAL expression traversal in Zope Page Templates, requiring restricted template editing permissions.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2021-32674?
CVE-2021-32674 is a high-severity code injection vulnerability in zopefoundation Zope, published on 8 Jun 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. This advisory extends the previous advisory at https://github.com/zopefoundation/Zope/security/advisories/GHSA-5pr9-v234-jw36 with additional cases of TAL expression traversal vulnerabilities. Most Python modules are not available for using in TAL expressions that you can add through-the-web, for example in Zope Page Templates. This restriction avoids file system access, for example via the 'os' module. But some of the untrusted modules are available indirectly through Python modules that are available for direct use. By default, you need to have the Manager role to add or edit Zope Page Templates through the web. Only sites that allow untrusted users to add/edit Zope Page Templates through the web are at risk. The problem has been fixed in Zope 5.2.1 and 4.6.1. The workaround is the same as for https://github.com/zopefoundation/Zope/security/advisories/GHSA-5pr9-v234-jw36: 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-2021-32674?
9 open source packages ship an affected version, including zope and Zope. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
zope PyPI | All versions | 4.6.1 |
zope PyPI | All versions | 4.6.1 |
zope PyPI | From 4.0 | 4.6.1, 5.2.1 |
zope PyPI | From 5.0 | 5.2.1 |
zope PyPI | From 5.0 | 5.2.1 |
Zope PyPI | All versions | 4.6.1 |
3 more packages
Zope PyPI | All versions | 4.6.1 |
Zope PyPI | From 5.0 | 5.2.1 |
Zope PyPI | From 5.0 | 5.2.1 |
Products include Zope Zope.
How do I fix CVE-2021-32674?
Upgrade zope to a fixed version for your release line: 4.6.1 or 5.2.1.
Upgrade, and never evaluate templates, expressions or code built from user input. More about Code injection.
Is CVE-2021-32674 being exploited?
There is no known exploitation of CVE-2021-32674 in the wild and no public exploit code.
Other vulnerabilities in zopefoundation Zope
- CVE-2000-0062 Zope DTML implementation Improper Authentication
- CVE-2000-1211 Zope does not properly perform security registration for legacy names
- CVE-2002-0170 Zope does not properly verify the access for objects with proxy roles
- CVE-2002-0688 ZCatalog plug-in for Zope allows anonymous users to bypass access restrictions
- CVE-2001-1227 Security feature bypass in n/a
Sources
Also known as GHSA-5vq5-pg3r-9ph3, GHSA-rpcg-f9q6-2mq6, PYSEC-2021-104.