CVE-2026-115477: Human-in-the-Loop Authorization Bypass in obsidian-tc

Vulnerability ID: CVE-2026-115477
CVSS Score: 7.1
Published: 2026-10-23

A high-severity authorization bypass vulnerability in obsidian-tc allows clients to bypass Human-In-The-Loop (HITL) confirmation prompts over Streamable HTTP deployments. Due to incomplete validation of returned prompt responses, an attacker echoing a signed requestState token can force execution of destructive vault operations even if a human user declines or cancels the prompt.

TL;DR

In obsidian-tc prior to version 1.31.4, echoing a valid requestState token causes the server to execute destructive tool calls regardless of whether the user explicitly declined or canceled the prompt.

Technical Details

• CWE ID: CWE-285 / CWE-863
• CVSS v4.0: 7.1 (CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N)
• Attack Vector: Network
• EPSS Score: N/A
• CISA KEV Status: Not Listed
• Exploit Status: No Public Weaponized Exploit
• Impact: High Integrity (Unauthorized Destructive Operations)

Affected Systems

• obsidian-tc over Streamable HTTP deployments with auth.jwtSecret configured
• obsidian-tc: >= 1.13.0, < 1.31.4 (Fixed in: 1.31.4)

Code Analysis

Commit: 101c91c

fix(mcp): inspect inputResponses and resolveElicitConfirmation before setting elicitState

mcp/elicit-form.ts: inspect inputResponses; set elicitState only if action === 'accept' && content.approve === true

Mitigation Strategies

• Upgrade obsidian-tc to version 1.31.4 or higher.
• Deploy obsidian-tc using stdio transport instead of Streamable HTTP.
• Unset auth.jwtSecret on HTTP deployments to force single-use token validation.

Remediation Steps:

1. Update the package dependency in package.json to obsidian-tc ^1.31.4.
2. Run npm install obsidian-tc@latest.
3. Restart the obsidian-tc MCP server.
4. Verify tool call confirmation behavior using a test decline request.

References

• GitHub Security Advisory GHSA-737x-cwfr-5vvc
• NVD CVE-2026-115477 Detail
• CVE Program Record CVE-2026-115477
• Fix Commit 101c91c656e2c2b88bcf3696a5da035f8c032c71
• GitHub Pull Request #969
• GitHub Issue #967
• Release v1.31.4
• Repository Changelog

Read the full report for CVE-2026-115477 on our website for more details including interactive diagrams and full exploit analysis.