High · CVSS 8.8CVE-2026-77363

obsidian-tc Streamable HTTP transport permits cross-origin loopback vault accessCVE-2026-77363

Answer in brief

CVE-2026-77363 records a High severity (CVSS 8.8) vulnerability in obsidian-tc Streamable HTTP transport permits cross-origin loopback vault access. The current sources do not mark it as known exploited. The current feed maps The-40-Thieves/obsidian-tc (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Oct 12, 2026Updated Oct 12, 2026Source checked Oct 12, 2026First seen by HOL Oct 12, 2026Material review Oct 12, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 8.8
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

CVSS is 8.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps The-40-Thieves/obsidian-tc (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
The-40-Thieves/obsidian-tcgeneric	<1.3.1	1.3.1

Recommended response

Check inventory. Check lockfiles and deployed manifests for The-40-Thieves/obsidian-tc.
Review the reported fix. Update The-40-Thieves/obsidian-tc to 1.3.1 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Oct 12, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Oct 12, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Oct 12, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.