CVE-2026-66829 — Security Box Score

CVE · referencelatest edition

Reference page — cumulative record through Wednesday, August 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2026-66829LOW

rrrene html_sanitize_ex — html_sanitize_ex HTML5 scrubber keeps attacker-supplied meta refresh, allowing forced cross-origin redirection

  AV  AC  AT  PR  UI  VC  VI  VA   CVSS    EPSS   %ile   KEV
   N   L   P   N   P   N   N   N    2.3   .0050   40.8     —

AFFECTED
  Product           Versions                                    Fixed
  html_sanitize_ex  0.3.1 –                                     —
  html_sanitize_ex  8976d64ea0b77d26093a94a43ec48a3978e8d028 –  9f7e38be51edc38f132dfe994f37af5cf5e0e76f

TIMELINE
  Aug 6   Reserved by EEF
  Aug 6   Published (CNA: EEF)
  Aug 18  PATCH SHIPPED — CVE-2026-66829 (rrrene html_sanitize_ex). Fixed in html_sanitize_ex 9f7e38be51edc38f132dfe994f37af5cf5e0e76f.

CWE-601 · CNA: EEF · CVSS v4.0 · 5 references · NVD status: Analyzed

Description

URL Redirection to Untrusted Site ('Open Redirect') vulnerability in the HTML5 scrubber in rrrene html_sanitize_ex allows a remote attacker to force visitors of a page to navigate to a site of the attacker's choosing via a <meta http-equiv="refresh"> element in sanitized HTML. HtmlSanitizeEx.html5/1 keeps attacker-supplied <meta> elements in its output. A meta element acts on the whole document rather than on the fragment it was embedded in, so it can also declare document-wide directives such as Content-Security-Policy. This is not cross-site scripting. Browsers do not navigate a meta refresh to a javascript: URL, so the uppercase JAVASCRIPT: filter bypass yields no script execution and none was demonstrated. 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.

Lifecycle

Complete event history — 3 events, chronological
Date	Event	Detail
August 6, 2026	Reserved	Reserved by EEF
August 6, 2026	Published	Published (CNA: EEF)
August 18, 2026	PATCH SHIPPED	PATCH SHIPPED — CVE-2026-66829 (rrrene html_sanitize_ex). Fixed in html_sanitize_ex 9f7e38be51edc38f132dfe994f37af5cf5e0e76f.

Affected

Affected products and packages — 2 rows
Vendor	Product / Package	Ecosystem	Version introduced	Fixed
rrrene	html_sanitize_ex	—	0.3.1	—
rrrene	html_sanitize_ex	—	8976d64ea0b77d26093a94a43ec48a3978e8d028	9f7e38be51edc38f132dfe994f37af5cf5e0e76f

Weaknesses

CWE-601

References (5)

https://cna.erlef.org/cves/CVE-2026-66829.html [related]
https://github.com/rrrene/html_sanitize_ex/commit/29454dc99513fd9b5b6429ab7b6695ad09889227 [patch]
https://github.com/rrrene/html_sanitize_ex/commit/9f7e38be51edc38f132dfe994f37af5cf5e0e76f [patch]
https://github.com/rrrene/html_sanitize_ex/security/advisories/GHSA-2c6f-3j54-xpcr [vendor-advisory, related]
https://osv.dev/vulnerability/EEF-CVE-2026-66829 [related]

Authoritative record: CVE-2026-66829 at cve.org

Vendors: rrrene

Weaknesses: CWE-601

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-66829 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Wednesday, August 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.