Vulnerability · Published Aug 6, 2026 · Assigned by EEF

CVE-2026-68749Quadratic regex backtracking in the html_sanitize_ex CSS scrubber allows CPU-exhaustion denial of service

High 8.2

In plain English

A high-severity regular-expression denial of service in html_sanitize_ex from rrrene. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.8% (higher than 57% of all known vulnerabilities).

Severity (CVSS 4.0)8.2High

Exploit odds (30 days)0.8%top 43.2% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official 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 1.4.5 and from 1.5.0-rc.0 before 1.5.3.

Affected products (as reported)

Vendor	Product	Versions
rrrene	html_sanitize_ex	0.3.1 – before 1.4.51.5.0-rc.0 – before 1.5.3
rrrene	html_sanitize_ex	21f90012eb21aa36f4e3701b7547e12faf0f3c8b – before *

Weakness: CWE-1333 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

In plain English

Official description

Affected products (as reported)

References