Restricted-resource slug disclosure via unchecked permalink redirect
Published Jan 28, 2026 · Updated Jan 28, 2026
Information disclosure in affected Discourse versions allows remote attackers to read restricted resource slugs through permalinks. The permalink controller redirected to a target URL without first enforcing the target's visibility rule, exposing its slug in the Location header and 404 search box. Exploitation requires a configured permalink to a private topic, category, post, or hidden tag; the reported consequence is confidentiality loss only.
Summary
What happened
Information disclosure in affected Discourse versions allows remote attackers to read restricted resource slugs through permalinks. The permalink controller redirected to a target URL without first enforcing the target's visibility rule, exposing its slug in the Location header and 404 search box. Exploitation requires a configured permalink to a private topic, category, post, or hidden tag; the reported consequence is confidentiality loss only.
The record
- CVE
- CVE-2026-23743
- Published
- Jan 28, 2026
- Updated
- Jan 28, 2026
- Vendor
- Discourse
- Product
- Discourse
- Classifications
- CWE-200, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jan 28, 2026CVE publishedPublication date reported by the CVE source.
- Jan 28, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=>= 2025.11.0-latest, < 2025.11.2
- Affected versionversion=>= 2025.12.0-latest, < 2025.12.1
- Affected versionversion=>= 2026.1.0-latest, < 2026.1.0
- Affected versionversion=< 3.5.4
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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