rrrene html_sanitize_ex 0.3.1/1.5.2 CSS scrubber HtmlSanitizeEx.Scrubber.CSS.scrub resource consumption

Summaryinfo

A vulnerability has been found in rrrene html_sanitize_ex 0.3.1/1.5.2 and classified as problematic. This affects the function HtmlSanitizeEx.Scrubber.CSS.scrub of the component CSS scrubber. This manipulation causes resource consumption. This vulnerability is handled as CVE-2026-68749. The attack can be initiated remotely. There is not any exploit available.

Detailsinfo

A vulnerability classified as problematic was found in rrrene html_sanitize_ex 0.3.1/1.5.2. Affected by this vulnerability is the function HtmlSanitizeEx.Scrubber.CSS.scrub of the component CSS scrubber. The manipulation with an unknown input leads to a resource consumption vulnerability. The CWE definition for the vulnerability is CWE-400. The product does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources. As an impact it is known to affect availability. The summary by CVE is:

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.

The advisory is shared at github.com. This vulnerability is known as CVE-2026-68749 since 07/31/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1499 for this issue.

Upgrading to version 1.5.3 eliminates this vulnerability.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Vendor

• rrrene

Name

• html_sanitize_ex

Version

• 0.3.1
• 1.5.2

Website

• Product: https://github.com/rrrene/html_sanitize_ex/

CPE 2.3info

• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Discussion