CVE-2021-24559: qyrr XSS — Exploit

Description

The Qyrr WordPress plugin before 0.7 does not escape the data-uri of the QR Code when outputting it in a src attribute, allowing for Cross-Site Scripting attacks. Furthermore, the data_uri_to_meta AJAX action, available to all authenticated users, only had a CSRF check in place, with the nonce available to users with a role as low as Contributor allowing any user with such role (and above) to set a malicious data-uri in arbitrary QR Code posts, leading to a Stored Cross-Site Scripting issue.

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CVSS v3.1 Score

5.4

MEDIUM

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

Weakness Type (CWE)

CWE-79 Cross-site Scripting (XSS)

Affected Products

Vendor	Product	Versions
patrickposner	qyrr	< 0.7

References

Exploits

https://wpscan.com/vulnerability/65a29976-163a-4bbf-a4e8-590ddc4b83f2/ https://wpscan.com/vulnerability/65a29976-163a-4bbf-a4e8-590ddc4b83f2/

Frequently Asked Questions

What is CVE-2021-24559? +

The Qyrr WordPress plugin before 0.7 does not escape the data-uri of the QR Code when outputting it in a src attribute, allowing for Cross-Site Scripting attacks. Furthermore, the data_uri_to_meta AJAX action, available to all authenticated users, only had a CSRF check in place, with the nonce available to users with a role as low as Contributor allowing any user with such role (and above) to set a malicious data-uri in arbitrary QR Code posts, leading to a Stored Cross-Site Scripting issue. It has a CVSS v3.1 base score of 5.4 (MEDIUM).

How severe is CVE-2021-24559? +

CVE-2021-24559 has a CVSS v3.1 score of 5.4 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-2021-24559? +

CVE-2021-24559 affects products from patrickposner, specifically: qyrr. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2021-24559? +

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-2021-24559