CyberRota Analysis
AI-GeneratedThe CSS scrubber in the html_sanitize_ex library is vulnerable to an inefficient regular expression complexity issue, allowing unauthenticated remote attackers to exhaust server CPU resources through specially crafted long CSS declarations. This can lead to application unresponsiveness due to CPU saturation, although no data is compromised. Organizations using html_sanitize_ex versions from 0.3.1 to before 1.5.3 should prioritize patching this vulnerability to prevent potential denial-of-service attacks.
Public Exploit Signal
A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.
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Original NVD Description
Inefficient Regular Expression Complexity vulnerability in the CSS scrubber in rrrene html_sanitize_ex allows an unauthenticated remote attacker to exhaust server CPU via a long CSS declaration in sanitized HTML. The declaration regex in HtmlSanitizeEx.Scrubber.CSS.scrub/1 matches the property name with an unbounded greedy [-\w]+ followed by a mandatory :, so a long run of word characters not followed by a colon makes the engine give back one character at a time and retry the colon at every start offset. The work is quadratic in the length of the run, and no length cap is applied to the CSS handed to the scrubber. An 80 KB <style> body costs roughly 2.4 seconds of scheduler time, so a few concurrent requests saturate the BEAM scheduler pool and make the application unresponsive. The impact is CPU exhaustion only. Nothing is read, modified or disclosed. This issue affects html_sanitize_ex: from 0.3.1 before 1.5.3.
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