CVE-2026-23743

Unknown Unknown - Not Provided

BaseFortify

Publication date: 2026-01-28

Last updated on: 2026-01-30

Assigner: GitHub, Inc.

Description

Discourse is an open source discussion platform. In versions prior to 3.5.4, 2025.11.2, 2025.12.1, and 2026.1.0, permalinks pointing to access-restricted resources (private topics, categories, posts, or hidden tags) were redirecting users to URLs containing the resource slug, even when the user didn't have access to view the resource. This leaked potentially sensitive information (e.g., private topic titles) via the redirect Location header and the 404 page's search box. This issue is patched in versions 3.5.4, 2025.11.2, 2025.12.1, and 2026.1.0. No known workarounds are available.

CVSS Scores

EPSS Scores

Probability:
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Meta Information

Published

2026-01-28

Last Modified

2026-01-30

Generated

2026-07-06

AI Q&A

2026-01-29

EPSS Evaluated

2026-07-05

NVD

CVE-2026-23743

EUVD

EUVD-2026-4861

Affected Vendors & Products

Vendor	Product	Version / Range
discourse	discourse	to 3.5.4 (exc)
discourse	discourse	From 2025.11.0 (inc) to 2025.11.2 (exc)
discourse	discourse	2025.12.0
discourse	discourse	2026.1.0

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-200	The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.

Attack-Flow Graph

Executive Summary

This vulnerability in Discourse versions prior to 3.5.4, 2025.11.2, 2025.12.1, and 2026.1.0 involves permalinks to access-restricted resources such as private topics, categories, posts, or hidden tags. When users without access clicked these permalinks, they were redirected to URLs containing the resource slug, which leaked potentially sensitive information like private topic titles through the redirect Location header and the 404 page's search box.

Impact Analysis

The vulnerability can lead to unintended disclosure of sensitive information by leaking resource identifiers and titles to unauthorized users. This could expose private discussions or confidential content to users who should not have access, potentially compromising privacy and confidentiality.

Mitigation Strategies

Upgrade Discourse to version 3.5.4, 2025.11.2, 2025.12.1, or 2026.1.0, as these versions contain the patch for this vulnerability. No known workarounds are available.

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