Improper input validation in Neos Form

CVE-2021-32697

neos/forms is an open source framework to build web forms. By crafting a special `GET` request containing a valid form state, a form can be submitted without invoking any validators. Form state is secured with an HMAC that is still verified. That means that this issue can only be exploited if Form Finishers cause side effects even if no form values have been sent. Form Finishers can be adjusted in a way that they only execute an action if the submitted form contains some expected data. Alternatively a custom Finisher can be added as first finisher. This regression was introduced with https://github.com/neos/form/commit/049d415295be8d4a0478ccba97dba1bb81649567

Vulnerability class: Drupalgeddon 2 (CVE-2018-7600)

EPSS: 0.011 (63.5th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N.

Affected products

  • Neos Form — versions >= 1.2.0, < 4.3.3, >= 5.0.0, < 5.0.9, >= 5.1.0, < 5.1.3

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2021-32697?
CVE-2021-32697 is a medium-severity vulnerability in Neos Form, classified under Improper Input Validation. CVSS score: 6.5/10. Published 2021-06-21.
How severe is CVE-2021-32697?
Medium severity. CVSS v3 base score is 6.5 out of 10.
Is CVE-2021-32697 known to be exploited?
1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.