CVE-2026-77143

High

Description

The frontend topic editing flow does not verify on the server side that the requesting visitor owns the topic being modified. As a result, a visitor who knows the identifier of a topic from the public forum can submit a modified update request for that topic directly and overwrite its content, without the application confirming ownership. Topic identifiers are visible in the public forum listing, and exploitation requires no privileged access or non-default configuration.

SeverityHigh

CVSS8.8

Exploit probability—

Product

Extension "Forum"

PublishedAug 25, 2026

First seenAug 25, 2026

Weakness typeCWE-862Missing authorization CWE-639Authorization bypass through user-controlled key

How to fix

Update

TYPO3 Extension "Forum"6.2.4, 5.0.1, 4.0.4 or later

Vendor advisories

typo3.org/security/advisory/typo3-ext-sa-2026-021

Affected products

Product	Affected versions	Fixed in
TYPO3 Extension "Forum"	6.0.0 ≤ v < 6.2.4, 5.0.0 ≤ v < 5.0.1, v < 4.0.4	6.2.4, 5.0.1, 4.0.4

Check your version

Choose the product and enter the version you run to see whether it falls in the affected range.

In the Intelligence 360 plan

Attack Surface Management

See the assets tied to your domains, the technologies they run and known vulnerabilities in one list.