CVE-2026-91157

Discourse: Media uploads remain publicly accessible after category permissions are restricted

HIGH
7.5
CVSS Score
Published: October 14, 2026 at 03:37 PM UTC
Updated: October 20, 2026 at 02:17 AM UTC
1 product affected across 1 vendorDiscourse

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Severity
HIGH7.5
Exploit prediction
EPSS 0.5%
SSVC
No known exploit

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

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

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.5HIGHGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
NONE
Availability
NONE
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-200CWE-863

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