Vulnerability-Lookup

GHSA-2GM2-HPG7-78F2

Vulnerability from github – Published: 2026-11-05 21:34 – Updated: 2026-11-05 21:34

Details

ChatCLI before v1.215.2 contains an improper validation vulnerability in the MCP OAuth login flow that uses server-supplied Protected Resource Metadata as the resource indicator without checking it matches the configured server URL. A malicious MCP server can declare another resource on the same authorization server, obtain the user's bearer token for it, and replay that token against the other resource.

Severity

8.0 (High)


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

5.1 (Medium)


                  
                    CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N

Show details on source website

JSON

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{
  "affected": [],
  "aliases": [
    "CVE-2026-123271"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-346"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-11-05T19:17:20Z",
    "severity": "MODERATE"
  },
  "details": "ChatCLI before v1.215.2 contains an improper validation vulnerability in the MCP OAuth login flow that uses server-supplied Protected Resource Metadata as the resource indicator without checking it matches the configured server URL. A malicious MCP server can declare another resource on the same authorization server, obtain the user\u0027s bearer token for it, and replay that token against the other resource.",
  "id": "GHSA-2gm2-hpg7-78f2",
  "modified": "2026-11-05T21:34:51Z",
  "published": "2026-11-05T21:34:51Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/diillson/chatcli/security/advisories/GHSA-95vg-3r9c-2v5q"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-123271"
    },
    {
      "type": "WEB",
      "url": "https://github.com/diillson/chatcli/commit/951fe24b8e090eae86bf8edb13a788916b1e6c91"
    },
    {
      "type": "WEB",
      "url": "https://github.com/diillson/chatcli/blob/359eb27debc4de78289a9662551a51ab4528e16c/cli/mcp/oauth.go#L477-L493"
    },
    {
      "type": "WEB",
      "url": "https://github.com/diillson/chatcli/releases/tag/v1.215.2"
    },
    {
      "type": "WEB",
      "url": "https://www.vulncheck.com/advisories/chatcli-before-1.215.2-origin-validation-error-via-unvalidated-mcp-oauth-resource-indicator"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
      "type": "CVSS_V4"
    }
  ]
}

CVE-2026-123271 (GCVE-0-2026-123271)

Vulnerability from cvelistv5 – Published: 2026-11-05 18:45 – Updated: 2026-11-05 18:45

Title

ChatCLI before v1.215.2 Origin Validation Error via Unvalidated MCP OAuth Resource Indicator

Summary

Severity

5.1 (Medium)


                        
                          CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N

8 (High)


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

CWE

CWE-346 - Origin Validation Error

Assigner

VulnCheck CNA under the mitre root

CNA scorecard B 84/100 over 7427 records in the last 180 days details

References

5 references

URL	Tags
https://github.com/diillson/chatcli/security/advi…	vendor-advisory
https://github.com/diillson/chatcli/commit/951fe2…	patch
https://github.com/diillson/chatcli/releases/tag/…	release-notes
https://github.com/diillson/chatcli/blob/359eb27d…	technical-description
https://www.vulncheck.com/advisories/chatcli-befo…	third-party-advisory

Impacted products

1 product

Vendor	Product	Version
diillson	ChatCLI	Affected: v1.159.0 , < v1.215.2 (semver)

Date Public

2026-10-11 00:00

Credits

Theodoros Lampropoulos diillson

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "packageURL": "pkg:golang/github.com/diillson/chatcli",
          "product": "ChatCLI",
          "repo": "https://github.com/diillson/chatcli",
          "vendor": "diillson",
          "versions": [
            {
              "lessThan": "v1.215.2",
              "status": "affected",
              "version": "v1.159.0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "Theodoros Lampropoulos"
        },
        {
          "lang": "en",
          "type": "remediation developer",
          "value": "diillson"
        }
      ],
      "datePublic": "2026-10-11T00:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "ChatCLI before v1.215.2 contains an improper validation vulnerability in the MCP OAuth login flow that uses server-supplied Protected Resource Metadata as the resource indicator without checking it matches the configured server URL. A malicious MCP server can declare another resource on the same authorization server, obtain the user\u0027s bearer token for it, and replay that token against the other resource."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "LOW",
            "attackRequirements": "PRESENT",
            "attackVector": "NETWORK",
            "baseScore": 5.1,
            "baseSeverity": "MEDIUM",
            "privilegesRequired": "NONE",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "HIGH",
            "subIntegrityImpact": "HIGH",
            "userInteraction": "ACTIVE",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "NONE",
            "vulnConfidentialityImpact": "NONE",
            "vulnIntegrityImpact": "NONE"
          },
          "format": "CVSS"
        },
        {
          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 8,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "scope": "CHANGED",
            "userInteraction": "REQUIRED",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:N",
            "version": "3.1"
          },
          "format": "CVSS"
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-346",
              "description": "Origin Validation Error",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-11-05T18:45:35.481Z",
        "orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
        "shortName": "VulnCheck"
      },
      "references": [
        {
          "name": "GitHub Security Advisory (GHSA-95vg-3r9c-2v5q)",
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://github.com/diillson/chatcli/security/advisories/GHSA-95vg-3r9c-2v5q"
        },
        {
          "tags": [
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          ],
          "url": "https://github.com/diillson/chatcli/commit/951fe24b8e090eae86bf8edb13a788916b1e6c91"
        },
        {
          "name": "ChatCLI v1.215.2 Release Notes",
          "tags": [
            "release-notes"
          ],
          "url": "https://github.com/diillson/chatcli/releases/tag/v1.215.2"
        },
        {
          "tags": [
            "technical-description"
          ],
          "url": "https://github.com/diillson/chatcli/blob/359eb27debc4de78289a9662551a51ab4528e16c/cli/mcp/oauth.go#L477-L493"
        },
        {
          "name": "VulnCheck Advisory: ChatCLI before v1.215.2 Origin Validation Error via Unvalidated MCP OAuth Resource Indicator",
          "tags": [
            "third-party-advisory"
          ],
          "url": "https://www.vulncheck.com/advisories/chatcli-before-1.215.2-origin-validation-error-via-unvalidated-mcp-oauth-resource-indicator"
        }
      ],
      "title": "ChatCLI before v1.215.2 Origin Validation Error via Unvalidated MCP OAuth Resource Indicator",
      "x_generator": {
        "engine": "vulncheck-endgame"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
    "assignerShortName": "VulnCheck",
    "cveId": "CVE-2026-123271",
    "datePublished": "2026-11-05T18:45:35.481Z",
    "dateReserved": "2026-11-05T18:19:12.338Z",
    "dateUpdated": "2026-11-05T18:45:35.481Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

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