CVE-2021-28121

Virtual Robots.txt before 1.10 does not block HTML tags in the robots.txt field

published August 12, 2021

CVSS
—
EPSS
2%
Percentile
76.6
In the wild
Unconfirmed
What it is

⚠️ A sneaky flaw allows HTML tags in a virtual robots.txt file, potentially giving unwanted visitors a peek behind the curtain! Think of it like a restaurant menu that not only lists the food but also accidentally includes the secret recipes — tempting for some, but risky for everyone involved! An attacker could exploit this vulnerability to manipulate the rules set in the robots.txt, effectively directing search engine crawlers to ignore sensitive areas of your site. This could lead to the exposure of confidential data or even a full-blown security breach, making it a worry worth addressing!

Put simply

Think of it like a restaurant menu that not only lists the food but also accidentally includes the secret recipes — tempting for some, but risky for everyone involved! This vulnerability occurs because the virtual robots.txt feature in versions before 1.10 does not properly sanitize HTML tags, allowing crafted entries that might mislead crawlers.

What to do

An attacker could exploit this vulnerability to manipulate the rules set in the robots.txt, effectively directing search engine crawlers to ignore sensitive areas of your site. This could lead to the exposure of confidential data or even a full-blown security breach, making it a worry worth addressing! Upgrade to version 1.10 or later to ensure that HTML tags are sanitized properly in the robots.txt file. Additionally, review your robots.txt configurations to confirm they adhere to security best practices. Don't forget to monitor your site's crawl behavior after the update! You've got this! With these steps, you're on your way to securing your site from unwanted sneaky peeks! 🛡️

The record
Technical detail
CVSS
Not scored
CVSS v4.0
Not supplied
EPSS
0.01669 · 76.6th percentile
Published
2021-08-12T22:00Z
EPSS history
Timeline
  • 12 AUG 22:00Z
    Virtual Robots.txt before 1.10 does not block HTML tags in the robots.txt field
    cvelistv5