# CVE-2026-77363: obsidian-tc HTTP transport DNS-rebinding and cross-origin vulnerability

Source: https://junglewise.ai/threats/cve-2026-77363-obsidian-tc-is-a-governed-agent-ready-model-context-protocol  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-12. Updated: 2026-10-16  
License: CC BY 4.0 with a link back

CVE-2026-77363 · Severity: critical · CVSS 9.6 · Published 2026-10-12

obsidian-tc is a Model Context Protocol server that provides programmatic access to Obsidian note vaults. Prior to version 1.3.1, when configured with the documented default loopback settings without authentication, a malicious web page could trick a user's browser into sending requests directly to the local MCP server and gain unrestricted access to all vault data. This allows attackers to steal notes, private information, and potentially modify vault contents.

Technologies: [obsidian-tc (npm)](https://junglewise.ai/threats/technologies/npm-obsidian-tc), [The-40-Thieves Obsidian-Tc](https://junglewise.ai/threats/technologies/obsidian-tc). Vendors: [npm](https://junglewise.ai/threats/vendors/npm), [The-40-Thieves](https://junglewise.ai/threats/vendors/the-40-thieves).

## Quick answers

**Is CVE-2026-77363 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-77363 being exploited in the wild.

**How severe is CVE-2026-77363?** Critical severity, with a CVSS score of 9.6, published 12 October 2026.

**Which products and versions are affected?** obsidian-tc (npm) < 1.3.1, SEMVER:introduced=0,fixed=1.3.1; The-40-Thieves Obsidian-Tc before 1.3.1.

**Is there a fix for CVE-2026-77363?** Yes. obsidian-tc (npm): upgrade to 1.3.1 or later. Until then: Disable the HTTP transport if not needed, or enable DNS-rebinding protection and configure allowedHosts and allowedOrigins as needed; switch to authentication mode other than 'none' to require bearer tokens for all HTTP requests. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-77363 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-77363?** Check whether you run obsidian-tc (npm) or The-40-Thieves Obsidian-Tc at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- obsidian-tc (npm): upgrade to 1.3.1 or later

  ```sh
  npm install obsidian-tc@1.3.1
  ```


Disable the HTTP transport if not needed, or enable DNS-rebinding protection and configure allowedHosts and allowedOrigins as needed; switch to authentication mode other than 'none' to require bearer tokens for all HTTP requests.

## Technical details

The Streamable HTTP transport fails to validate the Host and Origin headers or implement DNS-rebinding protection, allowing cross-origin POST requests from malicious web pages to http://127.0.0.1:&lt;port&gt;/mcp to bypass the documented loopback-only auth.mode:'none' default. An attacker-controlled web page can exploit this when served to a user with an active local MCP server, gaining full wildcard scopes and unrestricted vault access. Version 1.3.1 fixes this by adding header validation and DNS-rebinding protection before the auth pipeline.

## Affected products

- The-40-Thieves obsidian-tc before 1.3.1

## Identifiers

- CVE-2026-77363
- GHSA-pqh8-4pj7-32xx

## Timeline

- 2026-10-12: disclosed
- 2026-07-01: patched: Fix merged in commit 6428bfe

## References

- [https://github.com/The-40-Thieves/obsidian-tc/commit/6428bfe6fdfd43aa7b4b369be3aecd6a268fb928](https://github.com/The-40-Thieves/obsidian-tc/commit/6428bfe6fdfd43aa7b4b369be3aecd6a268fb928)
- [https://github.com/The-40-Thieves/obsidian-tc/pull/74](https://github.com/The-40-Thieves/obsidian-tc/pull/74)

## Related threats

- [obsidian-tc entity operations data loss through unserialized SQLite writes](https://junglewise.ai/threats/cve-2026-115478-obsidian-tc-is-a-governed-agent-ready-model-context-protocol)
- [obsidian-tc improper authorization in dispatch-gated tool execution](https://junglewise.ai/threats/cve-2026-115477-obsidian-tc-is-a-governed-agent-ready-model-context-protocol)
- [obsidian-tc information disclosure via bridge tools ACL bypass](https://junglewise.ai/threats/cve-2026-77362-obsidian-tc-is-a-governed-agent-ready-model-context-protocol)
- [obsidian-tc ACL bypass via symlink path resolution](https://junglewise.ai/threats/cve-2026-77361-obsidian-tc-is-a-governed-agent-ready-model-context-protocol)
- [obsidian-tc cross-vault authorization bypass](https://junglewise.ai/threats/cve-2026-77366-obsidian-tc-is-a-governed-agent-ready-model-context-protocol)