Vulnerability-Lookup

CVE-2026-66824 (GCVE-0-2026-66824)

Vulnerability from cvelistv5 – Published: 2026-07-27 19:58 – Updated: 2026-07-28 15:20

Title

Stored Cross-Site Scripting via Unsafe Capture Tree JSON Embedding

Summary

A stored cross-site scripting vulnerability existed in the capture tree visualization page. The application embedded the serialized capture tree directly into an inline JavaScript block using the Jinja safe filter. Because the tree data can contain values derived from captured and potentially attacker-controlled web content, a specially crafted value could prematurely terminate the surrounding <script> element and inject arbitrary HTML or JavaScript. The malicious code would execute in the browser of a user viewing the affected capture tree. Successful exploitation could allow an attacker to perform actions using the victim’s authenticated session, access information available to the victim, or modify application data within the permissions of the affected user. The patch removes the JSON data from the HTML document and retrieves it through a dedicated API endpoint. The client then processes the response using response.json(), preventing capture data from being interpreted as executable content within the original page’s HTML or JavaScript context.

Severity

9.2 (Critical)


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

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator (v2.0.3)

CWE

CWE-79 - Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting')

Assigner

CIRCL

References

1 reference

URL	Tags
https://github.com/Lookyloo/lookyloo/commit/39518…	patch

Impacted products

1 product

Vendor	Product	Version
lookyloo	lookyloo	Affected: 0 , ≤ 1.40.0 (semver)

Credits

Raphael Vinot Jeroen Pinoy

Show details on NVD website

JSON

To clipboard

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GCVE-1-2026-20140 (CVE-2026-66824)

Vulnerability from gna-1 – Published: 2026-07-27 19:56 – Updated: 2026-07-27 19:58

Title

Stored Cross-Site Scripting via Unsafe Capture Tree JSON Embedding

Summary

Severity

9.2 (Critical)


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

CWE

CWE-79 - Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting')

Assigner

GNA-1

References

1 reference

URL	Tags
https://github.com/Lookyloo/lookyloo/commit/39518…	patch

Impacted products

1 product

Vendor	Product	Version
lookyloo	lookyloo	Affected: 0 , ≤ 1.40.0 (semver)

Credits

Raphael Vinot Jeroen Pinoy

JSON

To clipboard

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GHSA-VJMW-PHG6-9F2X

Vulnerability from github – Published: 2026-07-27 21:31 – Updated: 2026-07-27 21:31

Details

Because the tree data can contain values derived from captured and potentially attacker-controlled web content, a specially crafted value could prematurely terminate the surrounding element and inject arbitrary HTML or JavaScript. The malicious code would execute in the browser of a user viewing the affected capture tree.

Successful exploitation could allow an attacker to perform actions using the victim’s authenticated session, access information available to the victim, or modify application data within the permissions of the affected user.

The patch removes the JSON data from the HTML document and retrieves it through a dedicated API endpoint. The client then processes the response using response.json(), preventing capture data from being interpreted as executable content within the original page’s HTML or JavaScript context.

Severity

9.2 (Critical)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-66824"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-27T21:17:17Z",
    "severity": "CRITICAL"
  },
  "details": "A stored cross-site scripting vulnerability existed in the capture tree visualization page. The application embedded the serialized capture tree directly into an inline JavaScript block using the Jinja safe filter.\n\nBecause the tree data can contain values derived from captured and potentially attacker-controlled web content, a specially crafted value could prematurely terminate the surrounding \u003cscript\u003e element and inject arbitrary HTML or JavaScript. The malicious code would execute in the browser of a user viewing the affected capture tree.\n\nSuccessful exploitation could allow an attacker to perform actions using the victim\u2019s authenticated session, access information available to the victim, or modify application data within the permissions of the affected user.\n\nThe patch removes the JSON data from the HTML document and retrieves it through a dedicated API endpoint. The client then processes the response using response.json(), preventing capture data from being interpreted as executable content within the original page\u2019s HTML or JavaScript context.",
  "id": "GHSA-vjmw-phg6-9f2x",
  "modified": "2026-07-27T21:31:29Z",
  "published": "2026-07-27T21:31:29Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-66824"
    },
    {
      "type": "WEB",
      "url": "https://github.com/Lookyloo/lookyloo/commit/395187b57322ab311363ccc290c010b180389009"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:N/SC:H/SI:N/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"
    }
  ]
}

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.

Action not permitted

CVE-2026-66824 (GCVE-0-2026-66824)

GCVE-1-2026-20140 (CVE-2026-66824)

GHSA-VJMW-PHG6-9F2X

Tags

Sightings

Nomenclature