CVE-2026-68749
Received
Received - Intake
Inefficient Regular Expression Complexity in html_sanitize_ex CSS Scrubber
Vulnerability report for CVE-2026-68749, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-08-06
Last updated on: 2026-08-06
Assigner: EEF
Description
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.
CVSS Scores
EPSS Scores
| Probability: | |
| Percentile: |
Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| rrrene | html_sanitize_ex | From 0.3.1 (inc) to 1.5.3 (exc) |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-1333 | The product uses a regular expression with an inefficient, possibly exponential worst-case computational complexity that consumes excessive CPU cycles. |
