Vulnerability-Lookup

GHSA-R46Q-WV4X-RJ72

Vulnerability from github – Published: 2026-09-02 03:31 – Updated: 2026-09-02 03:31

Details

BookStack before 26.05.4 contains a stored cross-site scripting vulnerability in the drawing upload endpoint that accepts unvalidated base64 content and stores it without content inspection. Attackers with editor permissions can upload SVG files containing scripts that execute in administrator browsers when accessed through the image gallery API without content-type validation or CSP headers.

Severity

8.7 (High)


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

9.3 (Critical)


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

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JSON

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{
  "affected": [],
  "aliases": [
    "CVE-2026-84695"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-02T01:17:24Z",
    "severity": "CRITICAL"
  },
  "details": "BookStack before 26.05.4 contains a stored cross-site scripting vulnerability in the drawing upload endpoint that accepts unvalidated base64 content and stores it without content inspection. Attackers with editor permissions can upload SVG files containing scripts that execute in administrator browsers when accessed through the image gallery API without content-type validation or CSP headers.",
  "id": "GHSA-r46q-wv4x-rj72",
  "modified": "2026-09-02T03:31:11Z",
  "published": "2026-09-02T03:31:11Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-84695"
    },
    {
      "type": "WEB",
      "url": "https://github.com/BookStackApp/BookStack/commit/ac0348a79f3ddd004ca87703948cb9c7d19a420a"
    },
    {
      "type": "WEB",
      "url": "https://github.com/BookStackApp/BookStack"
    },
    {
      "type": "WEB",
      "url": "https://github.com/BookStackApp/BookStack/blob/v26.05.3/app/Uploads/ImageService.php"
    },
    {
      "type": "WEB",
      "url": "https://github.com/BookStackApp/BookStack/releases/tag/v26.05.4"
    },
    {
      "type": "WEB",
      "url": "https://www.bookstackapp.com/blog/bookstack-release-v26-05-4"
    },
    {
      "type": "WEB",
      "url": "https://www.vulncheck.com/advisories/bookstack-before-26.05.4-stored-xss-via-drawing-upload"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/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"
    }
  ]
}

CVE-2026-84695 (GCVE-0-2026-84695)

Vulnerability from cvelistv5 – Published: 2026-09-02 00:37 – Updated: 2026-09-02 16:01

Title

BookStack before 26.05.4 Stored XSS via Drawing Upload

Summary

Severity

9.3 (Critical)


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

8.7 (High)


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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-09-02 13:42 UTC

CWE

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

Assigner

VulnCheck mitre root

References

6 references

URL	Tags
https://github.com/BookStackApp/BookStack	product
https://github.com/BookStackApp/BookStack/commit/…	patch
https://github.com/BookStackApp/BookStack/blob/v2…	technical-description
https://github.com/BookStackApp/BookStack/release…	release-notes
https://www.bookstackapp.com/blog/bookstack-relea…	vendor-advisory
https://www.vulncheck.com/advisories/bookstack-be…	third-party-advisory

Impacted products

1 product

Vendor	Product	Version
bookstackapp	bookstack	Affected: 0 , < 26.05.4 (custom) Unaffected: 26.05.4 (custom) cpe:2.3:a:bookstackapp:bookstack::::::::

Date Public

2026-08-19 00:00

Credits

Emanuele Cervelli

Show details on NVD website

JSON

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        "metrics": [
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            "other": {
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                "id": "CVE-2026-84695",
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                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-09-02T13:42:25.853414Z",
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          "shortName": "CISA-ADP"
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    ],
    "cna": {
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          "packageURL": "pkg:github/BookStackApp/BookStack",
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          "repo": "https://github.com/BookStackApp/BookStack",
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            },
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}

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

GHSA-R46Q-WV4X-RJ72

CVE-2026-84695 (GCVE-0-2026-84695)

Tags

Sightings

Nomenclature