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Vulnerability · Published Oct 14, 2026 · Assigned by GitHub_M

CVE-2026-91157Discourse: Media uploads remain publicly accessible after category permissions are restricted

High 7.5

In plain English

A high-severity information exposure in discourse from discourse. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 42% of all known vulnerabilities).

Severity (CVSS 3.1)7.5High
Exploit odds (30 days)0.5%top 58.3% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

Discourse is an open-source discussion platform. Prior to 2026.9.0, 2026.8.1, 2026.7.3, and 2026.1.9, sites with secure uploads enabled did not reconcile existing upload security metadata when a previously public category became read-restricted or when category permissions changed during a bulk import. Media and attachments uploaded while the category was public retained a public accessibility flag and remained reachable by anonymous users through their short upload URLs, including uploads associated with deleted topics. This issue is fixed in versions 2026.9.0, 2026.8.1, 2026.7.3, and 2026.1.9.

Affected products (as reported)

VendorProductVersions
discourse discourse < 2026.1.9>= 2026.7.0-latest, < 2026.7.3>= 2026.8.0-latest, < 2026.8.1>= 2026.9.0-latest, < 2026.9.0

Weakness: CWE-200, CWE-863 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

References