obsidian-tc HTTP transport lacks Origin/DNS-rebinding protection, enabling drive-by vault access on loopback

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

9.6 · CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

EPSS

• CVE-2026-77363: 0.15% estimated exploitation activity in the next 30 days; percentile 4.67 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

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.

Published by the source

23 Oct 2026, 18:29 UTC

Last modified by the source

23 Oct 2026, 18:45 UTC

Source last checked

26 Oct 2026, 13:07 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-pqh8-4pj7-32xx

2. Revision 2 · amended · 24 Oct 2026

   Amended from osv record GHSA-pqh8-4pj7-32xx

3. Revision 1 · created · 23 Oct 2026

   Published from ghsa record GHSA-pqh8-4pj7-32xx

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2026-77363

Advisory: obsidian-tc HTTP transport lacks Origin/DNS-rebinding protection, enabling drive-by vault access on loopback
IDs: CVE-2026-77363, GHSA-pqh8-4pj7-32xx
Record: https://patchnext.com/advisories/cve-2026-77363 (revision 3, source checked 26 Oct 2026, 13:07 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Critical (CVSS 9.6)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: obsidian-tc 1.3.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm obsidian-tc: affected < 1.3.1; fixed in 1.3.1

## Suggested inspection (read-only)
- `npm ls obsidian-tc --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on obsidian-tc.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-pqh8-4pj7-32xx (GitHub-reviewed advisory GHSA-pqh8-4pj7-32xx lists affected ranges: npm obsidian-tc >=0 <1.3.1)
- Verified: https://osv.dev/vulnerability/GHSA-pqh8-4pj7-32xx (OSV record GHSA-pqh8-4pj7-32xx lists affected ranges: npm obsidian-tc >=0 <1.3.1 (fixed))

Commands are suggestions: review each one before running it.