Security Resilience

CVE-2026-77363

Published
12 October 2026
Modified
13 October 2026
CVSS Score v3.1 8.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS Score 0.0016 4th percentile
Risk Priority 61 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2026-77363 is a high-severity Origin Validation Error (CWE-346) vulnerability. Its CVSS base score is 8.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique /etc/passwd and /etc/shadow (T1003.008); ranked at the 4th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

This vulnerability is AI-related — categorised as AI Agent Protocols and Integrations; in the Protocol-Specific Risks risk domain.

The strongest mitigations our analysis identified map to AC-3 (Access Enforcement) and AC-4 (Information Flow Enforcement) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

A07:2025 Authentication Failures

EU & UK References

Vulnerability Data

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…

more

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.

CWE(s)
CWE-346CWE-1385

AI Security AnalysisAI

AI Category
AI Agent Protocols and Integrations
Risk Domain
Protocol-Specific Risks
OWASP Top 10 for LLMs 2025
None mapped
Classification Reason
Matched keywords: model context protocol, mcp

Related Threats

MITRE ATT&CK Enterprise Techniques

T1003.008 /etc/passwd and /etc/shadow Credential Access
Adversaries may attempt to dump the contents of <code>/etc/passwd</code> and <code>/etc/shadow</code> to enable offline password cracking.
attack.mitre.org →
T1016 System Network Configuration Discovery Discovery
Adversaries may look for details about the network configuration and settings, such as IP and/or MAC addresses, of systems they access or through information discovery of remote systems.
attack.mitre.org →
T1021.004 SSH Lateral Movement
Adversaries may use [Valid Accounts](https://attack.
attack.mitre.org →
T1027.008 Stripped Payloads Stealth
Adversaries may attempt to make a payload difficult to analyze by removing symbols, strings, and other human readable information.
attack.mitre.org →
T1036 Masquerading Stealth
Adversaries may attempt to manipulate features of their artifacts to make them appear legitimate or benign to users and/or security tools.
attack.mitre.org →
T1036.003 Rename Legitimate Utilities Stealth
Adversaries may rename legitimate / system utilities to try to evade security mechanisms concerning the usage of those utilities.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-59950Shared CWE-1385, CWE-346
CVE-2023-26114Shared CWE-1385, CWE-346
CVE-2023-30856Shared CWE-1385, CWE-346
CVE-2023-0957Shared CWE-1385, CWE-346
CVE-2023-2886Shared CWE-1385, CWE-346
CVE-2023-2850Shared CWE-1385, CWE-346
CVE-2023-2848Shared CWE-1385, CWE-346
CVE-2023-49805Shared CWE-1385, CWE-346
CVE-2025-52882Shared CWE-1385
CVE-2025-61987Shared CWE-1385

Affected Assets

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V4.4.2

Mitigating Controls (NIST 800-53 r5) AI

AC-3 Access Enforcement partial match

Enforces approved authorizations on logical access, which can include origin checks before accepting WebSocket connections.

AC-4 Information Flow Enforcement partial match

Enforces information flow policies that can require validation of communication origins at system boundaries.

SC-23 Session Authenticity partial match

Protects authenticity of communications sessions, which origin validation helps ensure for WebSocket handshakes.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.AA-03 partial match
blocks

Origin validation is a required step when authenticating WebSocket connection requests.

PR.AA-05 partial match
blocks

Enforcing authorization policy on incoming connections can require origin checks.

PR.IR-01 partial match
blocks

Network-level controls that block unauthorized logical access can mitigate missing origin checks.

PR.PS-06 partial match
blocks

Secure SDLC practices directly require origin validation for WebSocket endpoints.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.5.14 Information transfer partial match
removes
A.5.15 Access control partial match
removes
A.5.16 Identity management partial match
removes
A.5.17 Authentication information partial match
removes
A.5.18 Access rights partial match
removes
A.8.10 Information deletion partial match
removes

Hardening callouts derived

DISA STIG baselines are authored against specific weaknesses. Where this CVE cites a broad weakness class, the mapping is not asserted at that abstraction (owner ruling, 2026-09-25: grade only at Base and below), so no rule is shown here rather than a rule shown against the wrong grain.

  • No fine-grained STIG row for CWE-346, a class-level weakness, and none of its children carries one either.

References