CVE-2026-23743

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 v3 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact NONE

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://github.com/discourse/discourse/security/advisories/GHSA-v5jw-rxc6-4cvv	Third Party Advisory

Configurations

Configuration 1 (hide)

OR	cpe:2.3:a:discourse:discourse:::::stable:::*
	cpe:2.3:a:discourse:discourse:::::stable:::*
	cpe:2.3:a:discourse:discourse:2025.12.0::::stable:::
	cpe:2.3:a:discourse:discourse:2026.1.0::::stable:::

History

30 Jan 2026, 20:31

Type	Values Removed	Values Added
CPE		cpe:2.3:a:discourse:discourse:2026.1.0::::stable::: cpe:2.3:a:discourse:discourse:::::stable:::* cpe:2.3:a:discourse:discourse:2025.12.0::::stable:::
First Time		Discourse Discourse discourse
References	~~() https://github.com/discourse/discourse/security/advisories/GHSA-v5jw-rxc6-4cvv -~~	() https://github.com/discourse/discourse/security/advisories/GHSA-v5jw-rxc6-4cvv - Third Party Advisory
CVSS	v2 : ~~unknown~~ v3 : ~~unknown~~	v2 : unknown v3 : 7.5

28 Jan 2026, 21:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-01-28 21:16

Updated : 2026-01-30 20:31

NVD link : CVE-2026-23743

Mitre link : CVE-2026-23743

CVE.ORG link : CVE-2026-23743

JSON object : View

Products Affected

discourse

discourse

CWE

CWE-200

Exposure of Sensitive Information to an Unauthorized Actor

{"id": "CVE-2026-23743", "cveTags": [], "metrics": {"cvssMetricV31": [{"type": "Primary", "source": "nvd@nist.gov", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.5, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "NONE", "confidentialityImpact": "HIGH"}, "impactScore": 3.6, "exploitabilityScore": 3.9}], "cvssMetricV40": [{"type": "Secondary", "source": "security-advisories@github.com", "cvssData": {"Safety": "NOT_DEFINED", "version": "4.0", "Recovery": "NOT_DEFINED", "baseScore": 6.9, "Automatable": "NOT_DEFINED", "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/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", "exploitMaturity": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED", "userInteraction": "NONE", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "subIntegrityImpact": "NONE", "vulnIntegrityImpact": "NONE", "integrityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "vulnAvailabilityImpact": "NONE", "availabilityRequirement": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "subConfidentialityImpact": "NONE", "vulnConfidentialityImpact": "LOW", "confidentialityRequirement": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED"}}]}, "published": "2026-01-28T21:16:11.597", "references": [{"url": "https://github.com/discourse/discourse/security/advisories/GHSA-v5jw-rxc6-4cvv", "tags": ["Third Party Advisory"], "source": "security-advisories@github.com"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Primary", "source": "security-advisories@github.com", "description": [{"lang": "en", "value": "CWE-200"}]}], "descriptions": [{"lang": "en", "value": "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."}], "lastModified": "2026-01-30T20:31:49.593", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:discourse:discourse:*:*:*:*:stable:*:*:*", "vulnerable": true, "matchCriteriaId": "FDBF21E2-1191-4020-A17A-0702DE4E6451", "versionEndExcluding": "3.5.4"}, {"criteria": "cpe:2.3:a:discourse:discourse:*:*:*:*:stable:*:*:*", "vulnerable": true, "matchCriteriaId": "539B5B85-44F0-408E-B994-08BB20EA9C26", "versionEndExcluding": "2025.11.2", "versionStartIncluding": "2025.11.0"}, {"criteria": "cpe:2.3:a:discourse:discourse:2025.12.0:*:*:*:stable:*:*:*", "vulnerable": true, "matchCriteriaId": "CCBF47A8-0D3F-4174-8084-CD3517BF272A"}, {"criteria": "cpe:2.3:a:discourse:discourse:2026.1.0:*:*:*:stable:*:*:*", "vulnerable": true, "matchCriteriaId": "F6CF5F98-F08F-4B28-BBE2-8296760A547E"}], "operator": "OR"}]}], "sourceIdentifier": "security-advisories@github.com"}