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TYPO3 Event Management EUVDEUVD-2026-65347

| CVE-2026-77128 MEDIUM
Missing Authorization (CWE-862)
2026-08-25 TYPO3 GHSA-w95p-wfvw-xgjm
6.3
CVSS 4.0 · Vendor: TYPO3
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Identify TYPO3 site with extension
  2. Delivery
    Craft URL with demand-override parameter
  3. Exploit
    Submit unauthenticated HTTP request
  4. Execution
    Extension skips enable-field check
  5. Impact
    Hidden or restricted events returned in response

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V8 - Authorization Authorization checks on every request
MITRE ATT&CK

1 technique across 1 tactic: Privilege Escalation

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Exploitation Conditions

Exploitation requires that the TYPO3 installation has the 'Event Management and Registration' extension installed and that the disableOverrideDemand plugin setting is NOT active (either because it was never configured or because the default does not enforce it). No authentication is required (CVSS PR:N), no user interaction is needed, and access is over the network. Exploitation is limited to reading hidden or time-restricted event records only - it does not grant write access, administrative access, or access to non-event data. The presence of disableOverrideDemand in an active state fully prevents exploitation.

Impact

The CVSS 4.0 vector (AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N) conveys a network-exploitable, low-complexity flaw with no privilege requirement, but the AT:P (attack requirements: present) metric correctly captures that exploitation depends on the disableOverrideDemand setting being inactive. Impact is narrowly scoped: only confidentiality of hidden or time-restricted event records is at risk - there is no integrity or availability dimension confirmed. The vulnerability is not listed in CISA KEV and no POC has been disclosed, keeping real-world urgency moderate despite the zero-authentication requirement. EPSS data is unavailable in the provided intelligence; given the niche product footprint and the opt-in mitigation that many hardened sites may already have active, actual exploitation probability is likely below what the raw CVSS score implies. The absence of version-range data in the CPE string means the full scope of exposure cannot be precisely bounded from available data alone.

Exploit ScenarioDerived

An unauthenticated attacker targeting a TYPO3 site with the Event Management and Registration extension appends the demand-override parameter to a public-facing event listing URL. Because the extension does not enforce enable-field restrictions on this parameter and disableOverrideDemand is inactive, the backend repository query returns records that should be hidden or not yet published, disclosing event details (titles, dates, descriptions) before their intended release. No authenticated session or prior reconnaissance beyond knowing the extension is installed is required.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
Patch available 0.4% exploitation probability (EPSS)

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AnalysisAIv1 – Aug 25, 2026

Unauthorized event disclosure in the TYPO3 "Event Management and Registration" extension allows unauthenticated remote users to view hidden or time-restricted events by supplying a demand-override query parameter that the extension fails to validate against its own enable-field restrictions. The vulnerability (CWE-862, Missing Authorization) is exploitable against any deployment where the disableOverrideDemand plugin setting is not explicitly activated - making non-hardened installs vulnerable by default. No public exploit code has been identified at time of analysis, and CVSS 4.0 scores this at 6.3 Medium with low confidentiality impact and no integrity or availability consequence.

RemediationAI

The primary remediation is to apply any patched extension release identified in the TYPO3 advisory at https://typo3.org/security/advisory/typo3-ext-sa-2026-023; an exact fixed version is not confirmed from the current data and should be verified there directly. As an immediate compensating control, administrators should activate the disableOverrideDemand plugin setting for all Event Management and Registration plugin instances - this is the explicit guard described in the CVE and directly blocks the attack path. The trade-off is that legitimate frontend demand-override functionality (e.g., event listing filters driven by URL parameters) will be disabled for end users. Operators relying on that behaviour should prioritize patch deployment over the workaround to avoid feature regression.

Affected VersionsENISA

Extension "Event management and registration" 9.0.0 <9.0.3
Extension "Event management and registration" 0 <5.9.3
Extension "Event management and registration" 7.0.0 <7.9.3
Extension "Event management and registration" 6.0.0 <6.7.2
Extension "Event management and registration" 8.0.0 <8.6.2

Affected Packages

euvd extension_event_management_and_registration fix: 5.9.3, 6.7.2, 7.9.3, 8.6.2, 9.0.3

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

The affected product is the TYPO3 CMS extension identified as 'Event Management and Registration' (CPE: cpe:2.3:a:typo3:extension_"event_management_and_registration":*:*:*:*:*:*:*:*). TYPO3 extensions expose frontend plugins that can be configured with plugin-level settings; this extension offers a demand-override mechanism allowing query parameters to influence repository-layer filtering (enable-fields are TYPO3's visibility controls for records, e.g., hidden or start/end time restrictions). CWE-862 (Missing Authorization) applies because the extension neglects to check whether the caller is permitted to override these controls before honoring the parameter. The guard exists as the disableOverrideDemand setting, but it is not enforced by default, making the protection opt-in rather than opt-out.

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Severity by source

Vendor (TYPO3) PRIMARY 6.3 MEDIUM
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
vuln.today AI 5.3 MEDIUM

Network-reachable with no auth or interaction; scope unchanged; only low confidentiality impact from reading hidden event records.

3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
4.0 AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N

Primary rating from Vendor (TYPO3).

CVSS VectorVendor: TYPO3

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
Present
Privileges Required
None
User Interaction
None
Vulnerable system: Confidentiality
Low
Vulnerable system: Integrity
None
Vulnerable system: Availability
None
Subsequent system: Confidentiality
None
Subsequent system: Integrity
None
Subsequent system: Availability
None

Lifecycle Timeline

1
Patch available
Aug 25, 2026 - 11:01 EUVD

DescriptionCVE.org

The extension fails to enforce enable-field restrictions on a repository query parameter. An unauthenticated remote user can pass a demand-override parameter to view hidden or time-restricted events, unless the disableOverrideDemand plugin setting is active. Exploitation of this issue requires only that disableOverrideDemand is not enabled.

Threat Intelligence Overview

EPSS Score
0.4%
Top 70% exploitable
Prevalence
Low
niche TYPO3 CMS extension, not broadly deployed
Data Quality
5 sources
Confidence: Medium

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC No
EPSS 0.4%
Patch available Yes
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation
None
System Exposure· derived
Open
Automatable
No
Human Impact· derived
Medium
Technical Impact
Partial

Priority Score

32
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +32
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.

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