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Fencer Vulns
high 8.3

CVE-2021-21357 json

Broken Access Control in Form Framework

published 2021-03-23 5 y ago modified 2026-07-08 4 mo ago also BIT-typo3-2021-21357 , EUVD-2021-0593 , GHSA-3vg7-jw9m-pc3f

cvss
8.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.6%
EPSS 1.6% chance of exploitation in 30 days, percentile 76%
public exploits
0
none known

Summary

TYPO3 is an open source PHP based web content management system. In TYPO3 before versions 8.7.40, 9.5.25, 10.4.14, 11.1.1 due to improper input validation, attackers can by-pass restrictions of predefined options and submit arbitrary data in the Form Designer backend module of the Form Framework. In the default configuration of the Form Framework this allows attackers to explicitly allow arbitrary mime-types for file uploads - however, default _fileDenyPattern_ successfully blocked files like _.htaccess_ or _malicious.php_. Besides that, attackers can persist those files in any writable directory of the corresponding TYPO3 installation. A valid backend user account with access to the form module is needed to exploit this vulnerability. This is fixed in versions 8.7.40, 9.5.25, 10.4.14, 11.1.1.

Patch / fix

  • packagist typo3/cms-form 8.7.40, 9.5.25, 10.4.14, 11.1.1
  • packagist typo3/cms-core 9.5.25, 10.4.14, 11.1.1
  • packagist typo3/cms 9.5.25, 10.4.14, 11.1.1
  • bitnami typo3 8.7.40, 9.5.25, 10.4.14, 11.1.1
  • typo3 typo3 8.7.40, 9.5.25, 10.4.14, 11.1.1

Exploit prediction

1.61% chance of exploitation in the next 30 days, higher than 76% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 8.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:H
GitHub 3.1 8.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:H/E:H/RL:O/RC:C
NVD 3.1 8.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:H
NVD 2.0 6.5 AV:N/AC:L/Au:S/C:P/I:P/A:P
OSV 3.1 8.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:H

Affected packages

ecosystem package affected fixed in
packagist typo3/cms-form
>=8.0.0, <8.7.40
>=9.0.0, <9.5.25
>=10.0.0, <10.4.14
>=11.0.0, <11.1.1
8.7.40
9.5.25
10.4.14
11.1.1
packagist typo3/cms-core
>=10.0.0, <10.4.14
>=11.0.0, <11.1.1
>=9.0.0, <9.5.25
10.4.14
11.1.1
9.5.25
packagist typo3/cms
>=10.0.0, <10.4.14
>=11.0.0, <11.1.1
>=9.0.0, <9.5.25
10.4.14
11.1.1
9.5.25
bitnami typo3
>=8.0.0, <8.7.40
>=9.0.0, <9.5.25
>=10.0.0, <10.4.14
>=11.0.0, <11.1.1
8.7.40
9.5.25
10.4.14
11.1.1

Affected products

  • TYPO3 TYPO3.CMS

Classification

Weakness
  • CWE-20 Improper Input Validation
  • CWE-22 Improper Limitation of a Pathname to a Restricted Directory
  • CWE-434 Unrestricted Upload of File with Dangerous Type

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.