MISP contains a cross-site scripting (XSS) vulnerability in the TAXII object viewer. When displaying a remote TAXII object, the JSON content of string properties was rendered directly into an HTML pre block without HTML-encoding. An attacker who can control or influence the content of a TAXII object (e.g., by publishing a malicious object to a TAXII server that the victim's MISP instance subscribes to) can inject arbitrary HTML or JavaScript that executes in the context of the victim's MISP session.
Preconditions:
- The victim must be an authenticated MISP user with access to the TAXII object viewer.
- The victim must open or view the crafted TAXII object.
Impact:
- Execution of arbitrary JavaScript in the victim's browser within the MISP application context.
- Potential theft of session tokens, API keys, or other sensitive data accessible from the MISP interface.
- Potential for performing actions on behalf of the authenticated user.
Affected versions: <2.5.48.
"}],"value":"MISP contains a cross-site scripting (XSS) vulnerability in the TAXII object viewer. When displaying a remote TAXII object, the JSON content of string properties was rendered directly into an HTML pre block without HTML-encoding. An attacker who can control or influence the content of a TAXII object (e.g., by publishing a malicious object to a TAXII server that the victim's MISP instance subscribes to) can inject arbitrary HTML or JavaScript that executes in the context of the victim's MISP session.\n\nPreconditions:\n\n- The victim must be an authenticated MISP user with access to the TAXII object viewer.\n\n- The victim must open or view the crafted TAXII object.\n\nImpact:\n\n- Execution of arbitrary JavaScript in the victim's browser within the MISP application context.\n\n- Potential theft of session tokens, API keys, or other sensitive data accessible from the MISP interface.\n\n- Potential for performing actions on behalf of the authenticated user.\n\nAffected versions: <2.5.48."}],"impacts":[{"capecId":"CAPEC-66","descriptions":[{"lang":"en","value":"CAPEC-66 Cross Site Scripting (XSS)"}]}],"metrics":[{"cvssV4_0":{"Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","Safety":"NOT_DEFINED","attackComplexity":"LOW","attackRequirements":"NONE","attackVector":"NETWORK","baseScore":6.2,"baseSeverity":"MEDIUM","privilegesRequired":"LOW","providerUrgency":"NOT_DEFINED","subAvailabilityImpact":"NONE","subConfidentialityImpact":"HIGH","subIntegrityImpact":"HIGH","userInteraction":"ACTIVE","valueDensity":"NOT_DEFINED","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N","version":"4.0","vulnAvailabilityImpact":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","vulnerabilityResponseEffort":"NOT_DEFINED"},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]},{"format":"SSVC","other":{"content":{"options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"Supplier","timestamp":"2026-10-02T15:47:29Z","version":"2.0.3"},"type":"SSVC"},"scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-79","description":"CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')","lang":"en","type":"CWE"}]}],"providerMetadata":{"dateUpdated":"2026-10-02T15:49:32.948Z","orgId":"5a6e4751-2f3f-4070-9419-94fb35b644e8","shortName":"CIRCL"},"references":[{"name":"Security patch","tags":["patch"],"url":"https://github.com/MISP/MISP/commit/1bed4ca0c"}],"solutions":[{"lang":"en","supportingMedia":[{"base64":false,"type":"text/html","value":"The fix applies HTML-encoding (via the h() helper) to the JSON string before it is interpolated into the HTML pre element. This ensures that any HTML or script markup present in the JSON string properties of a TAXII object is rendered as inert text rather than being parsed and executed by the browser, eliminating the XSS vector.
"}],"value":"The fix applies HTML-encoding (via the h() helper) to the JSON string before it is interpolated into the HTML pre element. This ensures that any HTML or script markup present in the JSON string properties of a TAXII object is rendered as inert text rather than being parsed and executed by the browser, eliminating the XSS vector."}],"title":"MISP TAXII Object Viewer Stored XSS via Unescaped JSON Output","x_gcve":[{"extensions":{"bcp-05-x-01":{"ai_annotations":[{"ai_level":"generated","description":"Draft vulnerability metadata was generated from a git-format patch using an Ollama-hosted language model. 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CAPEC-66 is the most specific CAPEC for XSS. The uncertainty is that the exact delivery mechanism (stored in a TAXII server vs. reflected) is not fully specified in the patch, but the core pattern of unencoded user-controlled data in an HTML context matches CAPEC-66 precisely."}],"commit":"1bed4ca0c990a4c285e8caa1d7efd91fec43eaca","confidence":"high","credits":[{"lang":"en","type":"reporter","value":"Jeroen Pinoy"},{"lang":"en","type":"remediation developer","value":"iglocska"},{"lang":"en","type":"remediation developer","value":"Claude Opus 5.5 (1M context)"}],"cvssRationale":"AV:N: The vulnerability is exploitable over the network via the MISP web interface. AC:L: No race conditions or special timing required; simply viewing the object triggers the XSS. AT:N: The malicious payload is already embedded in the TAXII object; no manipulation of the attack target is needed at exploit time. 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When displaying a remote TAXII object, the JSON content of string properties was rendered directly into an HTML pre block without HTML-encoding. An attacker who can control or influence the content of a TAXII object (e.g., by publishing a malicious object to a TAXII server that the victim's MISP instance subscribes to) can inject arbitrary HTML or JavaScript that executes in the context of the victim's MISP session.\n\nPreconditions:\n\n- The victim must be an authenticated MISP user with access to the TAXII object viewer.\n\n- The victim must open or view the crafted TAXII object.\n\nImpact:\n\n- Execution of arbitrary JavaScript in the victim's browser within the MISP application context.\n\n- Potential theft of session tokens, API keys, or other sensitive data accessible from the MISP interface.\n\n- Potential for performing actions on behalf of the authenticated user.\n\nAffected versions: <2.5.48.","Type":"Description","Title":"MISP TAXII Object Viewer Stored XSS via Unescaped JSON Output"}]}}}