CVE-2021-33511 Server-Side Request Forgery in Plone

What is CVE-2021-33511?

CVE-2021-33511 is a high-severity server-side request forgery vulnerability in Plone Plone, published on 21 May 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Plone though 5.2.4 allows SSRF via the lxml parser. This affects Diazo themes, Dexterity TTW schemas, and modeleditors in plone.app.theming, plone.app.dexterity, and plone.supermodel.

Weakness: CWE-918

Which versions are affected by CVE-2021-33511?

3 open source packages ship an affected version, including plone and Plone. It affects 1 product.

Products include Plone Plone.

How do I fix CVE-2021-33511?

Upgrade plone to 5.2.5 or later.

Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.

Is CVE-2021-33511 being exploited?

There is no known exploitation of CVE-2021-33511 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
• How this page is made

Also known as GHSA-gc9g-67cq-p7v4, PYSEC-2021-83.