High severity · published Oct 14, 2026
CVE-2026-91157
Discourse: Media uploads remain publicly accessible after category permissions are restricted
7.5
CVSS
0.5%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 41% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
DI
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 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-91157
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-91157
x_refsource_CONFIRM
https://github.com/discourse/discourse/security/advisories/GHSA-298h-xgw6-4pv3
x_refsource_MISC
https://github.com/discourse/discourse/commit/16017732981fdb3ee65d7b3c69c573610bf02aab
x_refsource_MISC
https://github.com/discourse/discourse/commit/83f5f9f1df7ddc79ec0950e1b2038ba659635708
x_refsource_MISC
https://github.com/discourse/discourse/commit/98f1c021d0e956cded5239a5d8a6afe2b9e1b7e7
x_refsource_MISC
https://github.com/discourse/discourse/commit/b2fb98394b2636b29e850f06b0029f8ca8b48458
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