What’s Vulnerable › Vulnerabilities

CVE-2026-46413: Discourse: Regular users can route multipart uploads into the admin backup store

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-07-09 · updated 2026-07-14
• Weakness: CWE-862

Description

Discourse is an open-source discussion platform. Prior to 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5, regular users could route direct S3 multipart uploads through ExternalUploadManager into the admin backup store. This issue is fixed in versions 2026.6.0, 2026.5.1, 2026.4.2, and 2026.1.5.

Affected products

• discourse: from 2026.1.0 before 2026.1.5; from 2026.4.0 before 2026.4.2; from 2026.5.0 before 2026.5.1; 2026.6.0 — fixed in 2026.1.5, 2026.4.2, 2026.5.1

How to fix

Upgrade to a fixed version: discourse 2026.1.5, 2026.4.2, 2026.5.1. Check the vendor advisory for mitigations.

References

• https://github.com/discourse/discourse/commit/1f1ded8dd361d81786bff17b35e1138d6ee299c0
• https://github.com/discourse/discourse/commit/7ddde266617b452152c1bf5f903f6c07be38fc40
• https://github.com/discourse/discourse/commit/a53df26dcf7e50ce2b20bfd5454a0c9d44b8fc7d
• https://github.com/discourse/discourse/commit/abaa664c5df84026efb2ca264ba0f5586c3f2b01
• https://github.com/discourse/discourse/releases/tag/v2026.1.5
• https://github.com/discourse/discourse/releases/tag/v2026.4.2
• https://github.com/discourse/discourse/releases/tag/v2026.5.1
• https://github.com/discourse/discourse/releases/tag/v2026.6.0
• https://github.com/discourse/discourse/security/advisories/GHSA-3mvf-q9rg-w6m7

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