GCVE-1-2026-20154 (CVE-2026-104907)

Vulnerability from gna-1 – Published: 2026-10-02 15:51 – Updated: 2026-10-02 15:51
VLAI
Title
MISP: JavaScript Injection via Remote Tag ID in Event Preview Inline Handler
Summary
MISP contains a cross-site scripting (XSS) vulnerability in the remote event preview page. When a linked (remote) MISP server is configured, the event preview renders tag identifiers inside an inline JavaScript onclick attribute. The tag ID value was HTML-escaped but not sanitized for the JavaScript string context, meaning a malicious linked server could supply a tag ID containing characters (such as a single quote) that break out of the JavaScript string literal and inject arbitrary script. Preconditions: - A linked/remote MISP server is configured and connected to the local instance. - The linked server supplies a crafted tag ID in an event. - An authenticated user views the event preview and interacts with the affected tag element. Impact: - Arbitrary JavaScript execution in the context of the viewing user's browser session, potentially allowing session hijacking, data exfiltration, or unauthorized actions on behalf of the user. Affected versions: MISP prior to the fix commit (v2.5.48 or later, exact boundary unconfirmed).
Severity
4.8 (Medium)
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N
SSVC
Exploitation: none Automatable: yes Technical Impact: partial
Supplier · CNA (v2.0.3)
Decision recorded 2026-10-02 15:50 UTC
CWE
  • CWE-79 - Cross-site Scripting (XSS)
  • CWE-116 - Improper Encoding or Escaping of Output
Assigner
GNA-1 This instance Scorecard
References
Impacted products
Vendor Product Version CPE status
MISP MISP Affected: 0 , < 2.5.48 (semver)
    cpe:2.3:a:misp:misp:*:*:*:*:*:*:*:*
Create a notification for this product.
Credits
Jeroen Pinoy iglocska Claude Opus 5.5 (1M context)
GCVE extensions
bcp-05-x-01
AI-assisted vulnerability information annotation
GCVE-BCP-05-X-01
Whole record AI-generated Human-reviewed GNA-1

Draft vulnerability metadata was generated from a git-format patch using an Ollama-hosted language model. Human validation is required before publication.

ai-computer-assisted:llm-generatedai-computer-assisted:classification
Model Source Identifier
qwen3.8:27b ollama qwen3.8:27b
bcp-05-x-02
Patch-to-vulnerability generation provenance
GCVE-BCP-05-X-02
Generator
patch2vuln.py on 2026-10-02 15:50
Model
qwen3.8:27b
Input
https://github.com/MISP/MISP/commit/70ad174dd.patch 048909e6f2d9…
Confidence
medium
Commit Subject Patch SHA-256
70ad174ddd43 fix: [security] Cast the remote tag id in the event preview 048909e6f2d9…
Fix summary

The vulnerability is remediated by casting the remote tag ID to an integer before embedding it in the inline JavaScript onclick handler. This ensures only a numeric value is rendered, eliminating the possibility of breaking out of the JavaScript string context with special characters.

Patch summary

In app/View/Servers/preview_event.ctp, the expression h($tag['id']) inside the onclick attribute's JavaScript string was replaced with (int)$tag['id']. This changes the output from an HTML-escaped string to a strictly integer value, preventing any non-numeric characters from being injected into the inline script context.

CVSS rationale

AV:N - the attack originates from a remote linked server over the network. AC:L - the injection is straightforward (embed a quote in a tag ID). AT:N - no special timing or race conditions required. PR:L - the attacker must be a configured linked server, which requires some level of trust/access but not full admin. UI:A - the victim must actively view the event preview and interact with the tag element. VC/VI/VA:N - the MISP server itself is not compromised; the impact is in the victim's browser. SC:N - no meaningful confidentiality impact on the subsequent component is guaranteed. SI:L - the injected script can perform limited actions (redirect, read page data, submit forms) in the user's session. SA:N - no availability impact on the subsequent component.

Weakness rationale
  • CWE-79 The tag ID is embedded in an inline JavaScript onclick handler where HTML escaping (h()) does not neutralize JavaScript string breakout characters. This is a classic case of improper output encoding for a JavaScript context, resulting in reflected XSS.
  • CWE-116 The root cause is using HTML entity encoding (h()) in a context that requires JavaScript string escaping. The encoding mechanism is inappropriate for the output context, which is a sub-category of the XSS issue.
Attack pattern rationale
  • CAPEC-1 The vulnerability is a reflected XSS where attacker-controlled data (a tag ID from a linked server) is injected into an inline JavaScript event handler without proper context-aware encoding. CAPEC-1 is the closest general match. The specific sub-technique is injection into a JavaScript string literal within an HTML attribute, which is not separately enumerated in CAPEC.
  • CAPEC-126 The attacker exploits the fact that the single-quote character (or similar) is not properly handled when the tag ID is placed inside a JavaScript string within an HTML attribute. The HTML escaping does not account for the JavaScript string delimiter. This CAPEC captures the character-handling aspect of the flaw. Uncertainty: CAPEC-1 is more directly about XSS; CAPEC-126 is included as a supplementary mapping for the encoding mismatch.
Assumptions to verify
  • The affected version boundary is inferred from the tag v2.5.48 with 28 commits after the fix; the exact first affected version is not stated in the patch.
  • The attacker is assumed to be a linked/remote MISP server that can control tag IDs in events shared with the local instance; the exact trust model and authentication for linked servers is not detailed in the patch.
  • CAPEC-126 is included as a supplementary mapping; the primary and most defensible mapping is CAPEC-1 (Cross Site Scripting).
  • The CVSS PR:L assumes that being a linked server requires some form of authenticated or trusted relationship, but the exact privilege level is not specified in the patch.
  • The Co-Authored-By line references an AI tool (Claude Opus 5.5); it is listed as a tool credit, not a human remediation developer.
  • The impact scope (SC/SI) is assessed conservatively; the actual XSS payload capability depends on the browser context and same-origin policy, which are not fully specified.
Model comparison

Selected qwen3.8:27b by deterministic-consensus-v1
The selected result is closest to model consensus; this heuristic does not establish factual correctness and human review remains required.

Model Score Agreement Confidence Assumptions
qwen3.8:27b 6 11 medium 6
bcp-05-x-03
Vulnerability handling and disclosure timeline
GCVE-BCP-05-X-03
  1. 2026-09-24 21:53 UTC Fix developed Corrective change authored (70ad174ddd438887687d40fc1e2e4e8b322a179e): fix: [security] Cast the remote tag id in the event preview
To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "cpes": [
            "cpe:2.3:a:misp:misp:*:*:*:*:*:*:*:*"
          ],
          "modules": [
            "Servers/preview_event"
          ],
          "product": "MISP",
          "programFiles": [
            "app/View/Servers/preview_event.ctp"
          ],
          "repo": "https://github.com/MISP/MISP",
          "vendor": "MISP",
          "versions": [
            {
              "lessThan": "2.5.48",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "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)"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "\u003cp\u003eMISP contains a cross-site scripting (XSS) vulnerability in the remote event preview page. When a linked (remote) MISP server is configured, the event preview renders tag identifiers inside an inline JavaScript onclick attribute. The tag ID value was HTML-escaped but not sanitized for the JavaScript string context, meaning a malicious linked server could supply a tag ID containing characters (such as a single quote) that break out of the JavaScript string literal and inject arbitrary script.\u003c/p\u003e\u003cp\u003ePreconditions:\u003c/p\u003e\u003cp\u003e- A linked/remote MISP server is configured and connected to the local instance.\u003c/p\u003e\u003cp\u003e- The linked server supplies a crafted tag ID in an event.\u003c/p\u003e\u003cp\u003e- An authenticated user views the event preview and interacts with the affected tag element.\u003c/p\u003e\u003cp\u003eImpact:\u003c/p\u003e\u003cp\u003e- Arbitrary JavaScript execution in the context of the viewing user\u0027s browser session, potentially allowing session hijacking, data exfiltration, or unauthorized actions on behalf of the user.\u003c/p\u003e\u003cp\u003eAffected versions: MISP prior to the fix commit (v2.5.48 or later, exact boundary unconfirmed).\u003c/p\u003e"
            }
          ],
          "value": "MISP contains a cross-site scripting (XSS) vulnerability in the remote event preview page. When a linked (remote) MISP server is configured, the event preview renders tag identifiers inside an inline JavaScript onclick attribute. The tag ID value was HTML-escaped but not sanitized for the JavaScript string context, meaning a malicious linked server could supply a tag ID containing characters (such as a single quote) that break out of the JavaScript string literal and inject arbitrary script.\n\nPreconditions:\n\n- A linked/remote MISP server is configured and connected to the local instance.\n\n- The linked server supplies a crafted tag ID in an event.\n\n- An authenticated user views the event preview and interacts with the affected tag element.\n\nImpact:\n\n- Arbitrary JavaScript execution in the context of the viewing user\u0027s browser session, potentially allowing session hijacking, data exfiltration, or unauthorized actions on behalf of the user.\n\nAffected versions: MISP prior to the fix commit (v2.5.48 or later, exact boundary unconfirmed)."
        }
      ],
      "impacts": [
        {
          "capecId": "CAPEC-1",
          "descriptions": [
            {
              "lang": "en",
              "value": "CAPEC-1 Cross Site Scripting"
            }
          ]
        },
        {
          "capecId": "CAPEC-126",
          "descriptions": [
            {
              "lang": "en",
              "value": "CAPEC-126 Exploiting Incorrectly Handled Special/Control Characters"
            }
          ]
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "Automatable": "NOT_DEFINED",
            "Recovery": "NOT_DEFINED",
            "Safety": "NOT_DEFINED",
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 4.8,
            "baseSeverity": "MEDIUM",
            "privilegesRequired": "LOW",
            "providerUrgency": "NOT_DEFINED",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "LOW",
            "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:N/SI:L/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": "2026-10-02T15:50:34Z",
              "version": "2.0.3"
            },
            "type": "SSVC"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-79",
              "description": "CWE-79 Cross-site Scripting (XSS)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-116",
              "description": "CWE-116 Improper Encoding or Escaping of Output",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "orgId": "00000000-0000-4000-9000-000000000000"
      },
      "references": [
        {
          "name": "Security patch",
          "tags": [
            "patch"
          ],
          "url": "https://github.com/MISP/MISP/commit/70ad174dd"
        }
      ],
      "solutions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "\u003cp\u003eThe vulnerability is remediated by casting the remote tag ID to an integer before embedding it in the inline JavaScript onclick handler. This ensures only a numeric value is rendered, eliminating the possibility of breaking out of the JavaScript string context with special characters.\u003c/p\u003e"
            }
          ],
          "value": "The vulnerability is remediated by casting the remote tag ID to an integer before embedding it in the inline JavaScript onclick handler. This ensures only a numeric value is rendered, eliminating the possibility of breaking out of the JavaScript string context with special characters."
        }
      ],
      "title": "MISP: JavaScript Injection via Remote Tag ID in Event Preview Inline Handler",
      "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 boundary is inferred from the tag v2.5.48 with 28 commits after the fix; the exact first affected version is not stated in the patch.",
                  "The attacker is assumed to be a linked/remote MISP server that can control tag IDs in events shared with the local instance; the exact trust model and authentication for linked servers is not detailed in the patch.",
                  "CAPEC-126 is included as a supplementary mapping; the primary and most defensible mapping is CAPEC-1 (Cross Site Scripting).",
                  "The CVSS PR:L assumes that being a linked server requires some form of authenticated or trusted relationship, but the exact privilege level is not specified in the patch.",
                  "The Co-Authored-By line references an AI tool (Claude Opus 5.5); it is listed as a tool credit, not a human remediation developer.",
                  "The impact scope (SC/SI) is assessed conservatively; the actual XSS payload capability depends on the browser context and same-origin policy, which are not fully specified."
                ],
                "capecRationale": [
                  {
                    "capecId": "CAPEC-1",
                    "rationale": "The vulnerability is a reflected XSS where attacker-controlled data (a tag ID from a linked server) is injected into an inline JavaScript event handler without proper context-aware encoding. CAPEC-1 is the closest general match. The specific sub-technique is injection into a JavaScript string literal within an HTML attribute, which is not separately enumerated in CAPEC."
                  },
                  {
                    "capecId": "CAPEC-126",
                    "rationale": "The attacker exploits the fact that the single-quote character (or similar) is not properly handled when the tag ID is placed inside a JavaScript string within an HTML attribute. The HTML escaping does not account for the JavaScript string delimiter. This CAPEC captures the character-handling aspect of the flaw. Uncertainty: CAPEC-1 is more directly about XSS; CAPEC-126 is included as a supplementary mapping for the encoding mismatch."
                  }
                ],
                "commit": "70ad174ddd438887687d40fc1e2e4e8b322a179e",
                "confidence": "medium",
                "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 attack originates from a remote linked server over the network. AC:L - the injection is straightforward (embed a quote in a tag ID). AT:N - no special timing or race conditions required. PR:L - the attacker must be a configured linked server, which requires some level of trust/access but not full admin. UI:A - the victim must actively view the event preview and interact with the tag element. VC/VI/VA:N - the MISP server itself is not compromised; the impact is in the victim\u0027s browser. SC:N - no meaningful confidentiality impact on the subsequent component is guaranteed. SI:L - the injected script can perform limited actions (redirect, read page data, submit forms) in the user\u0027s session. SA:N - no availability impact on the subsequent component.",
                "fixSummary": "The vulnerability is remediated by casting the remote tag ID to an integer before embedding it in the inline JavaScript onclick handler. This ensures only a numeric value is rendered, eliminating the possibility of breaking out of the JavaScript string context with special characters.",
                "generatedAt": "2026-10-02T15:50:34.593118Z",
                "generator": "patch2vuln.py",
                "model": "qwen3.8:27b",
                "modelComparison": {
                  "rankings": [
                    {
                      "agreementScore": 11,
                      "assumptionCount": 6,
                      "confidence": "medium",
                      "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": "048909e6f2d91cc9e6f920e8416edc5f9f44410eba1becc15373378f46a221de",
                "patchSummary": "In app/View/Servers/preview_event.ctp, the expression h($tag[\u0027id\u0027]) inside the onclick attribute\u0027s JavaScript string was replaced with (int)$tag[\u0027id\u0027]. This changes the output from an HTML-escaped string to a strictly integer value, preventing any non-numeric characters from being injected into the inline script context.",
                "patchTruncated": false,
                "patches": [
                  {
                    "commit": "70ad174ddd438887687d40fc1e2e4e8b322a179e",
                    "date": "Thu, 24 Sep 2026 23:53:31 +0200",
                    "patchSha256": "048909e6f2d91cc9e6f920e8416edc5f9f44410eba1becc15373378f46a221de",
                    "source": "https://github.com/MISP/MISP/commit/70ad174dd.patch",
                    "sourceUrl": "https://github.com/MISP/MISP/commit/70ad174dd.patch",
                    "subject": "fix: [security] Cast the remote tag id in the event preview"
                  }
                ],
                "source": "https://github.com/MISP/MISP/commit/70ad174dd.patch",
                "ssvc": {
                  "options": [
                    {
                      "Exploitation": "none"
                    },
                    {
                      "Automatable": "yes"
                    },
                    {
                      "Technical Impact": "partial"
                    }
                  ],
                  "role": "Supplier",
                  "timestamp": "2026-10-02T15:50:34Z",
                  "version": "2.0.3"
                },
                "subject": "fix: [security] Cast the remote tag id in the event preview",
                "tagVersionBoundary": {
                  "commits_after_fix": 28,
                  "repository": "https://github.com/MISP/MISP",
                  "tag": "v2.5.48",
                  "version": "2.5.48",
                  "version_type": "semver"
                },
                "weaknessRationale": [
                  {
                    "cweId": "CWE-79",
                    "rationale": "The tag ID is embedded in an inline JavaScript onclick handler where HTML escaping (h()) does not neutralize JavaScript string breakout characters. This is a classic case of improper output encoding for a JavaScript context, resulting in reflected XSS."
                  },
                  {
                    "cweId": "CWE-116",
                    "rationale": "The root cause is using HTML entity encoding (h()) in a context that requires JavaScript string escaping. The encoding mechanism is inappropriate for the output context, which is a sub-category of the XSS issue."
                  }
                ]
              }
            },
            "bcp-05-x-03": {
              "x_timeline": {
                "events": [
                  {
                    "description": "Corrective change authored (70ad174ddd438887687d40fc1e2e4e8b322a179e): fix: [security] Cast the remote tag id in the event preview",
                    "id": "evt-fix-developed-1",
                    "references": [
                      "https://github.com/MISP/MISP/commit/70ad174dd.patch"
                    ],
                    "timestamp": "2026-09-24T21:53:31Z",
                    "type": "fix-developed"
                  }
                ]
              }
            }
          },
          "recordType": "advisory",
          "vulnId": "GCVE-1-2026-20154"
        }
      ]
    }
  },
  "cveMetadata": {
    "assignerOrgId": "00000000-0000-4000-9000-000000000000",
    "cveId": "CVE-2026-104907",
    "datePublished": "2026-10-02T15:51:26.684280Z",
    "dateReserved": "2026-10-02T15:51:32.541Z",
    "dateUpdated": "2026-10-02T15:51:32.620284Z",
    "state": "PUBLISHED",
    "vulnId": "GCVE-1-2026-20154"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1"
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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.



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.