Extension "Event management and registration": Improper Neutralization of Special Elements Used in a Template Engine
CVE-2026-77129 is a high-severity improper neutralization of special elements used in a template engine vulnerability in Extension "Event management and registration" from TYPO3, with a CVSS 4.0 base score of 7.7 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. The record lists versions 9.0.3, 8.6.2, 7.9.3 as the first without the flaw, so updating Extension "Event management and registration" to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.4% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Extension "Event management and registration" to 9.0.3 or 8.6.2 or 7.9.3 or 6.7.2, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| TYPO3 | Extension "Event management and registration" | 9.0.0 up to, but not including, 9.0.3; 8.0.0 up to, but not including, 8.6.2; 7.0.0 up to, but not including, 7.9.3; 6.0.0 up to, but not including, 6.7.2; before 5.9.3 | 9.0.3, 8.6.2, 7.9.3, 6.7.2, 5.9.3 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Attack requirements
- PresentThe target must be in a specific state or configuration for the attack to work.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Confidentiality (vulnerable system)
- HighSerious loss of confidentiality on the vulnerable system.
- Integrity (vulnerable system)
- HighSerious loss of integrity on the vulnerable system.
- Availability (vulnerable system)
- HighSerious loss of availability on the vulnerable system.
- Confidentiality (other systems)
- NoneNo loss of confidentiality on systems beyond the vulnerable one.
- Integrity (other systems)
- NoneNo loss of integrity on systems beyond the vulnerable one.
- Availability (other systems)
- NoneNo loss of availability on systems beyond the vulnerable one.
Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. Scored by CNA.
Official description
The extension passes an editor-configurable email subject string directly into a Fluid template source without restriction. A backend user with edit access to the event plugin or Backend Module can supply Fluid ViewHelper syntax in this field to disclose sensitive data or execute TypoScript content objects. Exploitation of this issue requires an authenticated backend account with edit access to the event registration plugin or backend module.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Neutralization of Special Elements Used in a Template Engine
The product uses a template engine to insert or process externally-influenced input, but it does not neutralize or incorrectly neutralizes special elements or syntax that can be interpreted as template expressions or other code directives when processed by the engine.
How developers prevent this class of flaw
- Choose a template engine that offers a sandbox or restricted mode, or at least limits the power of any available expressions, function calls, or commands.
- Use the template engine's sandbox or restricted mode, if available.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other references
Recent Improper Neutralization of Special Elements Used in a Template Engine vulnerabilities
- 9.5 Critical severity
- 8.8 High severity
- 9.3 Critical severity
- 9.8 Critical severity
- 7.6 High severity
- 8.1 High severity
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