Form validation can be skipped

Description

Impact

By crafting a special GET request containing a valid form state, a form can be submitted without invoking any validators.
We consider the severity low because it is not possible to change any form values since the 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.

Patches

https://github.com/neos/form/commit/69de4219b1f58157e2be6b05811463875d75c246

Workarounds

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.

References

This regression was introduced with https://github.com/neos/form/commit/049d415295be8d4a0478ccba97dba1bb81649567
Original report: https://tickets.neos.io/#ticket/zoom/411 (internal)

Basic information

Type
reviewed
Severity
medium
Advisory on GitHub
Open advisory ↗
Repository advisory
Open repository advisory ↗
Source code
Not specified
Published (advisory)
2021-06-22 15:15:08 UTC
Updated
2024-02-07 18:18:58 UTC
GitHub reviewed
2021-06-21 17:39:52 UTC
NVD published
2021-06-21

EPSS Score

Score Percentile
0.40% 59.69%

CVSS Scores

Base score Version Severity Vector
6.5 3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.

Identifiers

CWEs

CWE id Name
CWE-20 Improper Input Validation

Credits

  • anianweber (analyst)

Affected packages (3)

Vulnerable version ranges and first patched releases as published by GitHub.

Ecosystem Package Vulnerable range First patched Vulnerable functions
composer neos/form >= 1.2.0, < 4.3.3 4.3.3
composer neos/form >= 5.0.0, < 5.0.9 5.0.9
composer neos/form >= 5.1.0, < 5.1.3 5.1.3

References

cvelogic Threat Intelligence