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CVE Record

CVE-2020-26216: Cross-Site Scripting in TYPO3 Fluid

TYPO3 Fluid before versions 2.0.8, 2.1.7, 2.2.4, 2.3.7, 2.4.4, 2.5.11 and 2.6.10 is vulnerable to Cross-Site Scripting. Three XSS vulnerabilities have been detected in Fluid: 1. TagBasedViewHelper allowed XSS through maliciously crafted additionalAttributes arrays by creating keys with attribute-closing quotes followed by HTML. When rendering such attributes, TagBuilder would not escape the keys. 2. ViewHelpers which used the CompileWithContentArgumentAndRenderStatic trait, and which declared escapeOutput = false, would receive the content argument in unescaped format. 3. Subclasses of AbstractConditionViewHelper would receive the then and else arguments in unescaped format. Update to versions 2.0.8, 2.1.7, 2.2.4, 2.3.7, 2.4.4, 2.5.11 or 2.6.10 of this typo3fluid/fluid package that fix the problem described. More details are available in the linked advisory.

HighCVSS 8Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2020-26216 is a high-severity cross-site scripting flaw in TYPO3 Fluid. A vulnerable site could render attacker-influenced content as executable browser script, potentially exposing user data or enabling actions in a victim's session. The public sources identify fixed Fluid patch releases.

Executive priority

Prioritize remediation for internet-facing or authenticated business applications using Fluid, because successful XSS can compromise user trust and sensitive browser-session data. This is patchable and should be handled through normal urgent dependency update workflows.

Technical view

TYPO3 Fluid failed to safely escape specific rendered values: crafted additionalAttributes keys, content arguments in certain ViewHelpers using CompileWithContentArgumentAndRenderStatic, and then/else arguments in AbstractConditionViewHelper subclasses. Affected typo3fluid/fluid branches are 2.0.x through 2.6.x below the listed fixed patch versions.

Likely exposure

Exposure is most likely in TYPO3 or PHP applications depending on typo3fluid/fluid versions 2.0.0-2.6.x below the fixed releases, especially where templates or custom ViewHelpers process user-influenced content or attributes.

Exploitation context

The bundle does not show CISA KEV listing or cited evidence of active exploitation. The CVSS vector indicates network reachability, no privileges required, user interaction required, high confidentiality and integrity impact, and high attack complexity.

Researcher notes

Evidence is strong for affected versions and fixed releases, but the provided bundle does not include proof-of-concept details or active exploitation reports. Keep analysis scoped to the three escaping failures described in the advisory.

Mitigation direction

  • Upgrade typo3fluid/fluid to the fixed patch release for the installed branch.
  • Confirm dependency lockfiles and deployed artifacts no longer include vulnerable Fluid versions.
  • Review custom ViewHelpers using additionalAttributes, disabled escaping, or conditional then/else arguments.
  • Follow the TYPO3 and GitHub advisories for any environment-specific upgrade guidance.

Validation and detection

  • Inventory applications using typo3fluid/fluid and record installed versions.
  • Compare installed versions against all affected ranges in the CVE bundle.
  • Review templates and custom ViewHelpers for user-influenced rendered attributes or content.
  • Confirm upgraded deployments run a fixed version: 2.0.8, 2.1.7, 2.2.4, 2.3.7, 2.4.4, 2.5.11, or 2.6.10.
Prepared
Confidence
high
Sources
5

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

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cwe · medium confidence lookup

CWE-79: User-session and phishing behavior lookup

Client-side and session-facing weaknesses should be reviewed alongside initial-access and user-execution behaviors. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

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cve · low confidence lookup

CVE-2020-26216 mapping review

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Vulnerability profileCVE Program record
Severity
High
CVSS
8 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:N

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
0Timeline events
0ADP providers
4Source links

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
8CVSS 3.1HighCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:N1.65.8Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

8High
CVSS 3.1 vector shape for CVE-2020-26216Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:N

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
TYPO3Fluid>= 2.0.0, < 2.0.8, >= 2.1.0, < 2.1.7, >= 2.2.0, < 2.2.4, >= 2.3.0, < 2.3.7, >= 2.4.0, < 2.4.4, >= 2.5.0, < 2.5.11, >= 2.6.0, < 2.6.10Listed
Weakness

CWE details

CWE-79

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-79 · source CWE mapping

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

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