MISP contains a stored cross-site script (XSS) vulnerability in the event graph preview feature.
The event graph preview image field was accepted and stored without server-side validation. On the client side, the stored value was rendered into an HTML img element's src attribute via string concatenation, allowing a crafted value to break out of the attribute context and inject arbitrary script.
Preconditions:
- An authenticated MISP user with the ability to create or modify an event graph entry.
- A second user (the victim) who views the event graph and triggers the preview popover.
Impact:
- Execution of arbitrary JavaScript in the victim's browser within the MISP application context.
- Potential theft of session tokens, cookies, or sensitive data accessible to the victim's browser.
- Potential for performing actions on behalf of the victim within the MISP application.
Affected: MISP versions prior to the fix (commit applied after v2.5.48).
" } ], "value": "MISP contains a stored cross-site script (XSS) vulnerability in the event graph preview feature.\n\nThe event graph preview image field was accepted and stored without server-side validation. On the client side, the stored value was rendered into an HTML img element's src attribute via string concatenation, allowing a crafted value to break out of the attribute context and inject arbitrary script.\n\nPreconditions:\n\n- An authenticated MISP user with the ability to create or modify an event graph entry.\n\n- A second user (the victim) who views the event graph and triggers the preview popover.\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, cookies, or sensitive data accessible to the victim's browser.\n\n- Potential for performing actions on behalf of the victim within the MISP application.\n\nAffected: MISP versions prior to the fix (commit applied after v2.5.48)." } ], "impacts": [ { "capecId": "CAPEC-1", "descriptions": [ { "lang": "en", "value": "CAPEC-1 Cross Site Scripting (XSS)" } ] } ], "metrics": [ { "cvssV4_0": { "Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "NONE", "attackVector": "NETWORK", "baseScore": 8.3, "baseSeverity": "HIGH", "privilegesRequired": "LOW", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "HIGH", "subIntegrityImpact": "HIGH", "userInteraction": "PASSIVE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:H/VA:N/SC:H/SI:H/SA:N", "version": "4.0", "vulnAvailabilityImpact": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "HIGH", "vulnerabilityResponseEffort": "NOT_DEFINED" }, "format": "CVSS", "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" } ] }, { "descriptions": [ { "cweId": "CWE-20", "description": "CWE-20 Improper Input Validation", "lang": "en", "type": "CWE" } ] } ], "providerMetadata": { "orgId": "5a6e4751-2f3f-4070-9419-94fb35b644e8", "shortName": "CIRCL", "dateUpdated": "2026-09-30T12:19:01.829Z" }, "references": [ { "name": "Security patch", "tags": [ "patch" ], "url": "https://github.com/MISP/MISP/commit/92c7ccc43" } ], "solutions": [ { "lang": "en", "supportingMedia": [ { "base64": false, "type": "text/html", "value": "The vulnerability is remediated by enforcing strict server-side validation of the preview image field, restricting it to a well-formed base64-encoded PNG data URL, and by replacing the client-side string-concatenation rendering with DOM-based attribute assignment that does not interpret the value as HTML.
" } ], "value": "The vulnerability is remediated by enforcing strict server-side validation of the preview image field, restricting it to a well-formed base64-encoded PNG data URL, and by replacing the client-side string-concatenation rendering with DOM-based attribute assignment that does not interpret the value as HTML." } ], "title": "MISP Stored Cross-Site Scripting (XSS) via Unvalidated Event Graph Preview Image", "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. Human validation is required before publication.", "gna_source": 1, "models": [ { "gna_source": 1, "identifier": "qwen3.8:27b", "name": "qwen3.8:27b", "source": "ollama" } ], "review_status": "full", "scope": "record", "tags": [ "ai-computer-assisted:llm-generated", "ai-computer-assisted:classification" ] } ] }, "bcp-05-x-02": { "x_patch2vuln": { "assumptions": [ "The affected version range is inferred from the tag_version_boundary (v2.5.48 with 43 commits after the fix); the exact fixed release version is not stated in the patch metadata.", "PR:L assumes the attacker needs at least a basic authenticated MISP account to create or modify an event graph entry; the patch does not specify the exact permission level required.", "UI:P assumes the victim triggers the XSS by viewing the event graph preview as part of normal workflow (hovering the plot button), which is a passive interaction rather than an active click on a crafted link.", "The CAPEC-1 mapping is direct and unambiguous given the explicit stored XSS identification in the commit message.", "The Co-Authored-By line referencing Claude Opus 4.8 is treated as a tool credit per the commit metadata; it is not a human contributor." ], "capecRationale": [ { "capecId": "CAPEC-1", "rationale": "The patch directly addresses a stored XSS where attacker-controlled data is rendered into a web page without proper encoding or validation. CAPEC-1 is the canonical attack pattern for XSS and is the closest match. No uncertainty in this mapping; the commit message explicitly identifies the issue as stored XSS." } ], "commit": "92c7ccc4398a64e61699bd79fb4010703616fc59", "confidence": "high", "credits": [ { "lang": "en", "type": "reporter", "value": "Bastien Bossiroy of NCIA" }, { "lang": "en", "type": "remediation developer", "value": "iglocska" }, { "lang": "en", "type": "remediation developer", "value": "Claude Opus 4.8" } ], "cvssRationale": "AV:N: exploited over the network via the MISP web interface. AC:L: no race conditions or special conditions required; storing a crafted value and viewing the graph is straightforward. AT:N: no manipulation of the attack target needed. PR:L: attacker needs a low-privilege authenticated MISP account to create/modify an event graph. UI:P: the victim passively triggers the XSS by viewing the event graph preview (hovering a button), a normal workflow action. VC/VI/VA:N: the MISP server itself is not compromised; the impact is in the victim's browser. SC:H: the attacker can read cookies, tokens, and data in the victim's session. SI:H: the attacker can perform authenticated actions as the victim. SA:N: no availability impact on the victim's system.", "fixSummary": "The vulnerability is remediated by enforcing strict server-side validation of the preview image field, restricting it to a well-formed base64-encoded PNG data URL, and by replacing the client-side string-concatenation rendering with DOM-based attribute assignment that does not interpret the value as HTML.", "generatedAt": "2026-09-30T11:21:27.655462Z", "generator": "patch2vuln.py", "model": "qwen3.8:27b", "modelComparison": { "rankings": [ { "agreementScore": 9, "assumptionCount": 5, "confidence": "high", "model": "qwen3.8:27b", "score": 6 } ], "selectedModel": "qwen3.8:27b", "selectionMethod": "deterministic-consensus-v1", "selectionNotice": "The selected result is closest to model consensus; this heuristic does not establish factual correctness and human review remains required." }, "patchSha256": "0ecb893de30056bc3f9609fcb8de43d60b1cedd6a1eea7d6aa53ef6d351d642a", "patchSummary": "In app/Model/EventGraph.php, a new validation rule is added for the preview_img field requiring it to match the regex /^data:image\\/png;base64,[A-Za-z0-9+\\/]*={0,2}$/ (allowing empty). In app/webroot/js/event-graph.js, two occurrences of string-concatenated img tag construction (return '