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CVE-2026-82450— BookStack before 26.05.4 Remote Code Execution via Book Cover

Quick assessment

Affected
bookstackapp bookstack
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Bookstackapp BookStack是Bookstackapp团队开源的一款文档管理系统。 Bookstackapp bookstack 26.05.4之前版本存在任意文件上传漏洞，该漏洞源于便携式ZIP导入功能未正确验证图片扩展名，允许具有Import Content和Create Books权限的用户上传PHP polyglot文件作为书籍封面，可能导致远程代码执行。

CVSS 8.8 · High EPSS 1.00% · P62

Affected Version Matrix 1

VendorProduct Version RangeStatus
bookstackapp bookstack < 26.05.4 affected
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I. Basic Information for CVE-2026-82450

Vulnerability Information
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Vulnerability Title
BookStack before 26.05.4 Remote Code Execution via Book Cover
Source: CVE Program / CVE List V5
Vulnerability Description
BookStack before 26.05.4 contains a remote code execution vulnerability in the portable ZIP import functionality that allows users with Import Content and Create Books permissions to upload a PHP polyglot file as a book cover. Attackers can bypass image extension validation by embedding a PHP file with a .php filename in the ZIP archive, which is stored in the public web root and executed by unauthenticated requests.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
危险类型文件的不加限制上传
Source: CVE Program / CVE List V5
Vulnerability Title
Bookstackapp bookstack 任意文件上传漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Bookstackapp BookStack是Bookstackapp团队开源的一款文档管理系统。 Bookstackapp bookstack 26.05.4之前版本存在任意文件上传漏洞，该漏洞源于便携式ZIP导入功能未正确验证图片扩展名，允许具有Import Content和Create Books权限的用户上传PHP polyglot文件作为书籍封面，可能导致远程代码执行。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
bookstackapp bookstack 0 ~ 26.05.4 -

II. Public POCs for CVE-2026-82450

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III. Intelligence Information for CVE-2026-82450

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Patches & Fixes for CVE-2026-82450 (1)

Vendor Advisories for CVE-2026-82450 (1)

Other References for CVE-2026-82450 (1)

IV. Related Vulnerabilities

Same product: bookstack
Same vendor: bookstackapp
Same weakness: CWE-434

V. Comments for CVE-2026-82450

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