Vulnerability-Lookup

CVE-2026-74234 (GCVE-0-2026-74234)

Vulnerability from cvelistv5 – Published: 2026-08-17 19:38 – Updated: 2026-08-17 19:55

Title

Legora < 2026-08-14 XSS via Mermaid gray-matter JavaScript Engine

Summary

Legora before 2026-08-14 contains a cross-site scripting vulnerability that allows attackers to achieve arbitrary JavaScript execution in a victim's browser by embedding a Mermaid block prefixed with a gray-matter JavaScript front-matter directive, causing the front-matter parser to invoke eval() before any SVG sanitization occurs. Attackers can exploit this flaw through influenced Mermaid diagram content to execute arbitrary JavaScript in the user's browser context, with elevated impact on Word and Outlook add-in surfaces where bearer session tokens are persisted in localStorage.

Severity

5.1 (Medium)


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

7.7 (High)


                        
                          CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:N

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-17 19:55 UTC

CWE

CWE-95 - Improper Neutralization of Directives in Dynamically Evaluated Code ('Eval Injection')

Assigner

VulnCheck mitre root

References

2 references

URL	Tags
https://legora.com/	product
https://www.vulncheck.com/advisories/legora-2026-…	third-party-advisory

Impacted products

1 product

Vendor	Product	Version	CPE status
Legora	Legora	Affected: 0 , < 2026-08-14 (date)	guessed

Date Public

2026-08-17 00:00

Credits

Mobasi Security Team

Show details on NVD website

JSON

To clipboard

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FKIE_CVE-2026-74234

Vulnerability from fkie_nvd - Published: 2026-08-17 20:16 - Updated: 2026-08-17 20:16

Severity

7.7 (High) - CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:N

Summary

References

	URL	Tags
	disclosure@vulncheck.com	https://legora.com/
	disclosure@vulncheck.com	https://www.vulncheck.com/advisories/legora-2026-08-14-xss-via-mermaid-gray-matter-javascript-engine

Impacted products

	Vendor	Product	Version

JSON

To clipboard

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    {
      "affectedData": [
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          "defaultStatus": "affected",
          "product": "Legora",
          "vendor": "Legora",
          "versions": [
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    }
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  "id": "CVE-2026-74234",
  "lastModified": "2026-08-17T20:16:46.813",
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}

GHSA-7M72-PF24-W743

Vulnerability from github – Published: 2026-08-17 21:31 – Updated: 2026-08-17 21:31

Details

Severity

7.7 (High)


                  
                    CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:N

5.1 (Medium)


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

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-74234"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-95"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-17T20:16:46Z",
    "severity": "MODERATE"
  },
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  "id": "GHSA-7m72-pf24-w743",
  "modified": "2026-08-17T21:31:24Z",
  "published": "2026-08-17T21:31:24Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-74234"
    },
    {
      "type": "WEB",
      "url": "https://legora.com"
    },
    {
      "type": "WEB",
      "url": "https://www.vulncheck.com/advisories/legora-2026-08-14-xss-via-mermaid-gray-matter-javascript-engine"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:H/SI:H/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.
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

CVE-2026-74234 (GCVE-0-2026-74234)

FKIE_CVE-2026-74234

GHSA-7M72-PF24-W743

Tags

Sightings

Nomenclature