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NVD / CVE Program· CNA GitHub_M

CVE-2021-21355: Unrestricted File Upload in Form Framework

HighCVSS 8.6 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 34/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 1.6% (FIRST EPSS); higher than 76.5% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: typo3/cms (Packagist) 10.4.14, 11.1.1, 9.5.25; typo3/cms-core (Packagist) 10.4.14, 11.1.1, 9.5.25; typo3/cms-form (Packagist) 10.4.14, 11.1.1, 8.7.40.

Low priority for now. Upgrade to typo3/cms (Packagist) 10.4.14, 11.1.1, 9.5.25; typo3/cms-core (Packagist) 10.4.14, 11.1.1, 9.5.25; typo3/cms-form (Packagist) 10.4.14, 11.1.1, 8.7.40 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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 the lack of ensuring file extensions belong to configured allowed mime-types, attackers can upload arbitrary data with arbitrary file extensions - however, default _fileDenyPattern_ successfully blocked files like _.htaccess_ or _malicious.php_. Besides that, _UploadedFileReferenceConverter_ transforming uploaded files into proper FileReference domain model objects handles possible file uploads for other extensions as well - given those extensions use the Extbase MVC framework, make use of FileReference items in their direct or inherited domain model definitions and did not implement their own type converter. In case this scenario applies, _UploadedFileReferenceConverter_ accepts any file mime-type and persists files in the default location. In any way, uploaded files are placed in the default location _/fileadmin/user_upload/_, in most scenarios keeping the submitted filename - which allows attackers to directly reference files, or even correctly guess filenames used by other individuals, disclosing this information. No authentication is required to exploit this vulnerability. This is fixed in versions 8.7.40, 9.5.25, 10.4.14, 11.1.1.

Published
Mar 22, 2021
Updated
Jun 16, 2026
EPSS
1.6% · 76th percentile

Report tools

JSON

Action score

34

Monitor

Low priority for now.

CVSS
34 / 40 · 8.6 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 1.6%

CNA vs NVD score

NVD
8.6
CNA · GitHub_M
8.6
agree

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2021-21355

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
typo3typo3

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • TYPO3 TYPO3.CMS

    • >= 8.0.0, <= 8.7.39, >= 9.0.0, <= 9.5.24, >= 10.0.0, <= 10.4.13, >= 11.0.0, <= 11.1.0affected
Affected versions · NVD (4)

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • typo3 typo38.0.0 and later · before 8.7.40
  • typo3 typo39.0.0 and later · before 9.5.25
  • typo3 typo310.0.0 and later · before 10.4.14
  • typo3 typo311.0.0 and later · before 11.1.1

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Packagisttypo3/cmsfrom 10.0.0 · before 10.4.1410.4.14
Packagisttypo3/cmsfrom 11.0.0 · before 11.1.111.1.1
Packagisttypo3/cmsfrom 9.0.0 · before 9.5.259.5.25
Packagisttypo3/cms-corefrom 10.0.0 · before 10.4.1410.4.14
Packagisttypo3/cms-corefrom 11.0.0 · before 11.1.111.1.1
Packagisttypo3/cms-corefrom 9.0.0 · before 9.5.259.5.25
Packagisttypo3/cms-formfrom 10.0.0 · before 10.4.1410.4.14
Packagisttypo3/cms-formfrom 11.0.0 · before 11.1.111.1.1
Packagisttypo3/cms-formfrom 8.0.0 · before 8.7.408.7.40
Packagisttypo3/cms-formfrom 9.0.0 · before 9.5.259.5.25

Same product

typo3: all records

Other highest-scoring records for the same primary product.

  • CVE-2009-0255The System extension Install tool in TYPO3 4.0.0 through 4.0.9, 4.1.0 through 4.1.7, and 4.2.0 through 4.2.3 creates the encryption key…
    60This week
  • CVE-2013-6288Unspecified vulnerability in the Apache Solr for TYPO3 (solr) extension before 2.8.3 for TYPO3 has unknown impact and remote attack…
    41Plan
  • CVE-2013-5303Unspecified vulnerability in the Store Locator (locator) extension before 3.1.5 for TYPO3 has unknown impact and remote attack vectors…
    41Plan

Published before and after this one in the same product

  • ← EarlierCVE-2021-21339Mar 22, 2021 · Cleartext storage of session identifier
    30Monitor
  • ← EarlierCVE-2021-21340Mar 22, 2021 · Cross-Site Scripting in Content Preview
    21Monitor
  • Later →CVE-2021-21357Mar 22, 2021 · Broken Access Control in Form Framework
    33Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Packagist:typo3/cms10.4.14Package registry (OSV)
Packagist:typo3/cms11.1.1Package registry (OSV)
Packagist:typo3/cms9.5.25Package registry (OSV)
Packagist:typo3/cms-core10.4.14Package registry (OSV)
Packagist:typo3/cms-core11.1.1Package registry (OSV)
Packagist:typo3/cms-core9.5.25Package registry (OSV)
Packagist:typo3/cms-form10.4.14Package registry (OSV)
Packagist:typo3/cms-form11.1.1Package registry (OSV)
Packagist:typo3/cms-form8.7.40Package registry (OSV)
Packagist:typo3/cms-form9.5.25Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

Not on record for this CVE: EPSS history · patch commit or PR link · researcher credit · variant or chain candidate · public bounty program.

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
low · data can be read
Integrity
high · data or configuration can be modified
Availability
low · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
Low
Integrity impact
High
Availability impact
Low

Weakness class (CWE)

CWE-434 · Unrestricted Upload of File with Dangerous Type

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:L

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

References

Show all references (2 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records