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

CVE-2020-6816

Medium
6.1/10

Summary

Bleach before 3.1.2 has a mutation-based XSS (mXSS) vulnerability, when RCDATA and either svg or math tags are whitelisted and the keyword argument strip=False. It happens due to improper sanitization of the RCDATA tags (script, noscript, style, noframes, xmp, noembed and iframe) when placed under svg or math, allowing the browser to execute arbitrary HTML in RCDATA on the victim's browser.

  • LOW
  • NETWORK
  • LOW
  • CHANGED
  • REQUIRED
  • NONE
  • LOW
  • NONE

CWE-79 - Cross Site Scripting

Cross-Site Scripting, commonly referred to as XSS, is the most dominant class of vulnerabilities. It allows an attacker to inject malicious code into a pregnable web application and victimize its users. The exploitation of such a weakness can cause severe issues such as account takeover, and sensitive data exfiltration. Because of the prevalence of XSS vulnerabilities and their high rate of exploitation, it has remained in the OWASP top 10 vulnerabilities for years.

References

Advisory Timeline

  • Published