# CVE-2026-77363: obsidian-tc Streamable HTTP transport permits cross-origin loopback vault access

> A malicious web page can access local Obsidian vaults via the MCP server's HTTP transport when authentication is disabled, bypassing origin checks.

- **Severity:** High 8.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 12 Oct 2026
- **Updated:** 13 Oct 2026
- **Also known as:** GHSA-pqh8-4pj7-32xx

## What is CVE-2026-77363?

CVE-2026-77363 is a high-severity server-side request forgery vulnerability in The-40-Thieves obsidian-tc, published on 12 Oct 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

obsidian-tc is a governed, agent-ready Model Context Protocol server for Obsidian vaults. Prior to 1.3.1, the Streamable HTTP transport does not validate the Host or Origin header or enable DNS-rebinding protection. When the documented loopback configuration uses auth.mode set to none, a malicious web page can send requests to the local MCP endpoint and receive unrestricted vault access through the http-local caller. Version 1.3.1 fixes the vulnerability by enabling host, origin, and DNS-rebinding validation.

Weakness: CWE-346 (Origin Validation Error), CWE-1385 (Missing Origin Validation in WebSockets)

## Which versions are affected by CVE-2026-77363?

2 open source packages ship an affected version, including obsidian-tc.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `obsidian-tc` | npm | All versions | 1.3.1 |
| `obsidian-tc` | npm | All versions | 1.3.1 |

## How do I fix CVE-2026-77363?

Upgrade obsidian-tc to 1.3.1 or later.

## Is CVE-2026-77363 being exploited?

There is no known exploitation of CVE-2026-77363 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-77363 and fix it if it is affected.

What it is: CVE-2026-77363 is a high-severity server-side request forgery vulnerability in The-40-Thieves obsidian-tc, published on 12 Oct 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-77363 in the wild and no public exploit code.

Affected packages and fixed versions:
- obsidian-tc (npm): affected all versions; fixed in 1.3.1
- obsidian-tc (npm): affected all versions; fixed in 1.3.1

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-77363/ (Markdown: https://insights.sbomify.com/CVE-2026-77363/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-77363
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-77363
- OSV: https://osv.dev/vulnerability/CVE-2026-77363

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-77363/
Summaries are generated and may contain mistakes; the official description above is the record.