CVE-2026-77363
obsidian-tc Streamable HTTP transport permits cross-origin loopback vault access
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- Required
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
obsidian-tc Streamable HTTP transport permits cross-origin loopback vault access
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.
- Record
CVE-2026-77363- CVSS 3.1
- 8.8 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - Weakness
- CWE-346, CWE-1385
- Updated
- 2026-11-02
EUVDEUVD-2026-97733
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.
- Record
EUVD-2026-97733- CVSS 3.1
- 8.8 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-pqh8-4pj7-32xx
obsidian-tc HTTP transport lacks Origin/DNS-rebinding protection, enabling drive-by vault access on loopback
Impact
The Streamable HTTP transport was constructed without enableDnsRebindingProtection/allowedHosts/allowedOrigins and performed no Origin-header validation. With the documented auth.mode: "none" loopback default, a drive-by web page could POST http://127.0.0.1/mcp and receive caller http-local with scopes ["*"] — full vault read/write — via DNS rebinding / a forged Origin.
Patches
Fixed in 1.3.1. Upgrade to >= 1.3.1. The transport now enables DNS-rebinding protection and allowed hosts/origins and returns HTTP 403 on an invalid Origin (per MCP 2025-11-25).
Workarounds
Do not expose the HTTP transport with auth.mode: "none"; require JWT auth, or bind to a non-loopback interface behind a proxy that validates Origin.
- Record
GHSA-pqh8-4pj7-32xx- CVSS 3.1
- 9.6 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H - Weakness
- CWE-346, CWE-1385
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2026-77363- CVSS 3.1
- 8.8 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - Weakness
- CWE-346, CWE-1385
- Updated
- 2026-11-02
OSV
obsidian-tc Streamable HTTP transport permits cross-origin loopback vault access
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.
- Record
CVE-2026-77363- CVSS 3.1
- 8.8 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - Weakness
- CWE-1385, CWE-346
- Updated
- 2026-11-02
OSVGHSA-pqh8-4pj7-32xx
obsidian-tc HTTP transport lacks Origin/DNS-rebinding protection, enabling drive-by vault access on loopback
Impact
The Streamable HTTP transport was constructed without enableDnsRebindingProtection/allowedHosts/allowedOrigins and performed no Origin-header validation. With the documented auth.mode: "none" loopback default, a drive-by web page could POST http://127.0.0.1/mcp and receive caller http-local with scopes ["*"] — full vault read/write — via DNS rebinding / a forged Origin.
Patches
Fixed in 1.3.1. Upgrade to >= 1.3.1. The transport now enables DNS-rebinding protection and allowed hosts/origins and returns HTTP 403 on an invalid Origin (per MCP 2025-11-25).
Workarounds
Do not expose the HTTP transport with auth.mode: "none"; require JWT auth, or bind to a non-loopback interface behind a proxy that validates Origin.
- Record
GHSA-pqh8-4pj7-32xx- CVSS 3.1
- 9.6 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H - Weakness
- CWE-1385, CWE-346
- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
obsidian-tcnpm |
before 1.3.1 | 1.3.1 |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-77363 is a high vulnerability (CVSS 8.8) in The-40-thieves Obsidian-tc, published October 12, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.15%, the 4th percentile. Fixed in obsidian-tc 1.3.1.
References
github.com/The-40-Thieves/obsidian-tc/security/advisories/GHSA-pqh8-4pj7-32xx
nvd.nist.gov/vuln/detail/cve-2026-77363