High severity · published Oct 12, 2026
CVE-2026-77363
obsidian-tc Streamable HTTP transport permits cross-origin loopback vault access
8.8
CVSS
0.2%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 5% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
OB
obsidian-tc · The-40-Thieves
< 1.3.1 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-77363
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-77363
x_refsource_CONFIRM
https://github.com/The-40-Thieves/obsidian-tc/security/advisories/GHSA-pqh8-4pj7-32xx
x_refsource_MISC
https://github.com/The-40-Thieves/obsidian-tc/pull/74
x_refsource_MISC
https://github.com/The-40-Thieves/obsidian-tc/commit/6428bfe6fdfd43aa7b4b369be3aecd6a268fb928
x_refsource_MISC
https://github.com/The-40-Thieves/obsidian-tc/releases/tag/v1.3.1
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