Vulnerability-Lookup

GHSA-VH6M-26HW-4322

Vulnerability from github – Published: 2026-09-04 12:30 – Updated: 2026-09-04 12:30

Details

A cross-site request forgery (CSRF) vulnerability exists in MISP due to form-security and CSRF protections being disabled based on whether an incoming request was identified as a REST request.

MISP's REST detection can be influenced by request properties such as the URL suffix or the HTTP Accept header. Because Accept: application/json can be supplied by a cross-origin page without requiring a CORS preflight, an attacker could cause a request originating from another website to be treated as REST traffic. MISP would consequently disable its normal form-security and CSRF validation even though the request was authenticated using the victim's existing browser session.

An unauthenticated remote attacker could exploit this behavior by convincing an authenticated MISP user to visit or interact with a malicious web page. The attacker's page could then issue crafted requests to susceptible state-changing MISP endpoints using the victim's privileges. Depending on the permissions of the victim and the targeted endpoint, this could allow unauthorized modification, creation, publication, or removal of data and other state changes.

The vulnerability originates from granting the form-security exemption based on _isRest() rather than on the authentication mechanism used by the request. The patch changes this behavior so that CSRF and form-security exemptions are granted only when the request actually carries a MISP API key. Session-authenticated REST-style requests remain subject to CSRF protection. The fix also introduces support for transmitting CSRF tokens through the X-CSRF-Token header for legitimate same-origin AJAX requests. Such a header cannot normally be attached by a cross-origin page without triggering a CORS preflight, preventing it from being used to reproduce the original attack.

Severity

6.2 (Medium)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-85547"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-352"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-04T10:17:14Z",
    "severity": "MODERATE"
  },
  "details": "A cross-site request forgery (CSRF) vulnerability exists in MISP due to form-security and CSRF protections being disabled based on whether an incoming request was identified as a REST request.\n\nMISP\u0027s REST detection can be influenced by request properties such as the URL suffix or the HTTP Accept header. Because Accept: application/json can be supplied by a cross-origin page without requiring a CORS preflight, an attacker could cause a request originating from another website to be treated as REST traffic. MISP would consequently disable its normal form-security and CSRF validation even though the request was authenticated using the victim\u0027s existing browser session.\n\nAn unauthenticated remote attacker could exploit this behavior by convincing an authenticated MISP user to visit or interact with a malicious web page. The attacker\u0027s page could then issue crafted requests to susceptible state-changing MISP endpoints using the victim\u0027s privileges. Depending on the permissions of the victim and the targeted endpoint, this could allow unauthorized modification, creation, publication, or removal of data and other state changes.\n\nThe vulnerability originates from granting the form-security exemption based on _isRest() rather than on the authentication mechanism used by the request. The patch changes this behavior so that CSRF and form-security exemptions are granted only when the request actually carries a MISP API key. Session-authenticated REST-style requests remain subject to CSRF protection.\nThe fix also introduces support for transmitting CSRF tokens through the X-CSRF-Token header for legitimate same-origin AJAX requests. Such a header cannot normally be attached by a cross-origin page without triggering a CORS preflight, preventing it from being used to reproduce the original attack.",
  "id": "GHSA-vh6m-26hw-4322",
  "modified": "2026-09-04T12:30:56Z",
  "published": "2026-09-04T12:30:56Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-85547"
    },
    {
      "type": "WEB",
      "url": "https://github.com/MISP/MISP/commit/f82646727"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:L/VA:L/SC:N/SI:L/SA:H/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-2026-85547 (GCVE-0-2026-85547)

Vulnerability from cvelistv5 – Published: 2026-09-04 09:40 – Updated: 2026-09-04 09:40

Title

Cross-Site Request Forgery via Attacker-Controlled REST Detection in MISP

Summary

A cross-site request forgery (CSRF) vulnerability exists in MISP due to form-security and CSRF protections being disabled based on whether an incoming request was identified as a REST request. MISP's REST detection can be influenced by request properties such as the URL suffix or the HTTP Accept header. Because Accept: application/json can be supplied by a cross-origin page without requiring a CORS preflight, an attacker could cause a request originating from another website to be treated as REST traffic. MISP would consequently disable its normal form-security and CSRF validation even though the request was authenticated using the victim's existing browser session. An unauthenticated remote attacker could exploit this behavior by convincing an authenticated MISP user to visit or interact with a malicious web page. The attacker's page could then issue crafted requests to susceptible state-changing MISP endpoints using the victim's privileges. Depending on the permissions of the victim and the targeted endpoint, this could allow unauthorized modification, creation, publication, or removal of data and other state changes. The vulnerability originates from granting the form-security exemption based on _isRest() rather than on the authentication mechanism used by the request. The patch changes this behavior so that CSRF and form-security exemptions are granted only when the request actually carries a MISP API key. Session-authenticated REST-style requests remain subject to CSRF protection. The fix also introduces support for transmitting CSRF tokens through the X-CSRF-Token header for legitimate same-origin AJAX requests. Such a header cannot normally be attached by a cross-origin page without triggering a CORS preflight, preventing it from being used to reproduce the original attack.

Severity

6.2 (Medium)


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

CWE

CWE-352 - Cross-Site Request Forgery (CSRF)

Assigner

CIRCL ENISA root

References

1 reference

URL	Tags
https://github.com/MISP/MISP/commit/f82646727	patch

Impacted products

1 product

Vendor	Product	Version
misp	misp	Affected: 0 , ≤ 2.5.45 (semver)

Credits

Andras Iklody (the Insomniac MISP lead dev) Scottish Government - National Cyber Team Peter James

Show details on NVD website

JSON

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "misp",
          "repo": "https://github.com/MISP/MISP/",
          "vendor": "misp",
          "versions": [
            {
              "lessThanOrEqual": "2.5.45",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "remediation developer",
          "value": "Andras Iklody"
        },
        {
          "lang": "en",
          "type": "finder",
          "value": "Scottish Government - National Cyber Team"
        },
        {
          "lang": "en",
          "type": "finder",
          "value": "Peter James"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "\u003cp\u003eA cross-site request forgery (CSRF) vulnerability exists in MISP due to form-security and CSRF protections being disabled based on whether an incoming request was identified as a REST request.\u003c/p\u003e\u003cp\u003eMISP\u0027s REST detection can be influenced by request properties such as the URL suffix or the HTTP \u003ccode\u003eAccept\u003c/code\u003e header. Because \u003ccode\u003eAccept: application/json\u003c/code\u003e can be supplied by a cross-origin page without requiring a CORS preflight, an attacker could cause a request originating from another website to be treated as REST traffic. MISP would consequently disable its normal form-security and CSRF validation even though the request was authenticated using the victim\u0027s existing browser session.\u003c/p\u003e\u003cp\u003eAn unauthenticated remote attacker could exploit this behavior by convincing an authenticated MISP user to visit or interact with a malicious web page. The attacker\u0027s page could then issue crafted requests to susceptible state-changing MISP endpoints using the victim\u0027s privileges. Depending on the permissions of the victim and the targeted endpoint, this could allow unauthorized modification, creation, publication, or removal of data and other state changes.\u003c/p\u003e\u003cp\u003eThe vulnerability originates from granting the form-security exemption based on \u003ccode\u003e_isRest()\u003c/code\u003e rather than on the authentication mechanism used by the request. The patch changes this behavior so that CSRF and form-security exemptions are granted only when the request actually carries a MISP API key. Session-authenticated REST-style requests remain subject to CSRF protection.\u003cbr\u003eThe fix also introduces support for transmitting CSRF tokens through the \u003ccode\u003eX-CSRF-Token\u003c/code\u003e header for legitimate same-origin AJAX requests. Such a header cannot normally be attached by a cross-origin page without triggering a CORS preflight, preventing it from being used to reproduce the original attack.\u003c/p\u003e\u003cbr\u003e"
            }
          ],
          "value": "A cross-site request forgery (CSRF) vulnerability exists in MISP due to form-security and CSRF protections being disabled based on whether an incoming request was identified as a REST request.\n\nMISP\u0027s REST detection can be influenced by request properties such as the URL suffix or the HTTP Accept header. Because Accept: application/json can be supplied by a cross-origin page without requiring a CORS preflight, an attacker could cause a request originating from another website to be treated as REST traffic. MISP would consequently disable its normal form-security and CSRF validation even though the request was authenticated using the victim\u0027s existing browser session.\n\nAn unauthenticated remote attacker could exploit this behavior by convincing an authenticated MISP user to visit or interact with a malicious web page. The attacker\u0027s page could then issue crafted requests to susceptible state-changing MISP endpoints using the victim\u0027s privileges. Depending on the permissions of the victim and the targeted endpoint, this could allow unauthorized modification, creation, publication, or removal of data and other state changes.\n\nThe vulnerability originates from granting the form-security exemption based on _isRest() rather than on the authentication mechanism used by the request. The patch changes this behavior so that CSRF and form-security exemptions are granted only when the request actually carries a MISP API key. Session-authenticated REST-style requests remain subject to CSRF protection.\nThe fix also introduces support for transmitting CSRF tokens through the X-CSRF-Token header for legitimate same-origin AJAX requests. Such a header cannot normally be attached by a cross-origin page without triggering a CORS preflight, preventing it from being used to reproduce the original attack."
        }
      ],
      "impacts": [
        {
          "capecId": "CAPEC-62",
          "descriptions": [
            {
              "lang": "en",
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      "metrics": [
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          "cvssV4_0": {
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            "Recovery": "NOT_DEFINED",
            "Safety": "NOT_DEFINED",
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 6.2,
            "baseSeverity": "MEDIUM",
            "privilegesRequired": "NONE",
            "providerUrgency": "NOT_DEFINED",
            "subAvailabilityImpact": "HIGH",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "LOW",
            "userInteraction": "ACTIVE",
            "valueDensity": "NOT_DEFINED",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:L/VA:L/SC:N/SI:L/SA:H",
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            "vulnAvailabilityImpact": "LOW",
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            "vulnerabilityResponseEffort": "NOT_DEFINED"
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        "dateUpdated": "2026-09-04T09:40:54.018Z",
        "orgId": "5a6e4751-2f3f-4070-9419-94fb35b644e8",
        "shortName": "CIRCL"
      },
      "references": [
        {
          "tags": [
            "patch"
          ],
          "url": "https://github.com/MISP/MISP/commit/f82646727"
        }
      ],
      "source": {
        "discovery": "UNKNOWN"
      },
      "title": "Cross-Site Request Forgery via Attacker-Controlled REST Detection in MISP",
      "x_generator": {
        "engine": "Vulnogram 0.2.0"
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  "cveMetadata": {
    "assignerOrgId": "5a6e4751-2f3f-4070-9419-94fb35b644e8",
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    "cveId": "CVE-2026-85547",
    "datePublished": "2026-09-04T09:40:54.018Z",
    "dateReserved": "2026-09-04T09:40:50.773Z",
    "dateUpdated": "2026-09-04T09:40:54.018Z",
    "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.

Detection rules are retrieved from Rulezet.

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.

Action not permitted

GHSA-VH6M-26HW-4322

CVE-2026-85547 (GCVE-0-2026-85547)

Tags

Sightings

Nomenclature