CVE-2021-3988: calibre-web XSS — Exploit & Fix

Description

A Cross-site Scripting (XSS) vulnerability exists in janeczku/calibre-web, specifically in the file `edit_books.js`. The vulnerability occurs when editing book properties, such as uploading a cover or a format. The affected code directly inserts user input into the DOM without proper sanitization, allowing attackers to execute arbitrary JavaScript code. This can lead to various attacks, including stealing cookies. The issue is present in the code handling the `#btn-upload-cover` change event.

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CVSS v3.1 Score

6.1

MEDIUM

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

Weakness Type (CWE)

CWE-79 Cross-site Scripting (XSS)

Affected Products

Vendor	Product	Versions
janeczku	calibre-web	< 0.6.15

References

Advisories & Patches

https://github.com/janeczku/calibre-web/commit/7ad419dc8c12180e842a82118f4866ac3d074bc5

Exploits

https://huntr.com/bounties/fa4c8fd1-7846-4dad-9112-2c07461f0609

Frequently Asked Questions

What is CVE-2021-3988? +

A Cross-site Scripting (XSS) vulnerability exists in janeczku/calibre-web, specifically in the file `edit_books.js`. The vulnerability occurs when editing book properties, such as uploading a cover or a format. The affected code directly inserts user input into the DOM without proper sanitization, allowing attackers to execute arbitrary JavaScript code. This can lead to various attacks, including stealing cookies. The issue is present in the code handling the `#btn-upload-cover` change event. It has a CVSS v3.1 base score of 6.1 (MEDIUM).

How severe is CVE-2021-3988? +

CVE-2021-3988 has a CVSS v3.1 score of 6.1 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2021-3988? +

CVE-2021-3988 affects products from janeczku, specifically: calibre-web. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2021-3988? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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CVE-2021-3988