CVE-2026-66829Network attack vectorHinoki check available

Forced cross-origin redirection via retained meta refresh

Published Aug 6, 2026 · Updated Aug 6, 2026

Open redirect in René Föhring html_sanitize_ex 0.3.1 through 1.4.4 and 1.5.0-rc.0 through 1.5.2 allows remote attackers to redirect page visitors. HtmlSanitizeEx.html5/1 and HTML5-derived custom scrubbers retain attacker-supplied meta refresh elements in sanitized fragments, where browsers apply them as document-wide directives. The sanitized output must be rendered to other users; the demonstrated consequence is forced cross-origin navigation, not script execution.

CVSS severity2.3
Low
EPSS probability0.50%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Open redirect in René Föhring html_sanitize_ex 0.3.1 through 1.4.4 and 1.5.0-rc.0 through 1.5.2 allows remote attackers to redirect page visitors. HtmlSanitizeEx.html5/1 and HTML5-derived custom scrubbers retain attacker-supplied meta refresh elements in sanitized fragments, where browsers apply them as document-wide directives. The sanitized output must be rendered to other users; the demonstrated consequence is forced cross-origin navigation, not script execution.

The record

CVE
CVE-2026-66829
Published
Aug 6, 2026
Updated
Aug 6, 2026
Vendor
René Föhring
Product
html_sanitize_ex
Classifications
CWE-601, CAPEC-154
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 6, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 6, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0.3.1 <1.5.3
  2. Affected versionversion=8976d64ea0b77d26093a94a43ec48a3978e8d028 <9f7e38be51edc38f132dfe994f37af5cf5e0e76f

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

René Föhring · html_sanitize_exversion=0.3.1 <1.5.3; version=8976d64ea0b77d26093a94a43ec48a3978e8d028 <9f7e38be51edc38f132dfe994f37af5cf5e0e76f

Published CVSS scores

2.3Erlang Ecosystem FoundationCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N
6.1NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-601URL Redirection to Untrusted Site ('Open Redirect')
CAPEC-154Resource Location Spoofing

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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