Origin spoofing via right-truncated long hostnames
Published May 11, 2026 · Updated May 11, 2026
Address-bar spoofing in Zen Browser before 1.19.12b allows remote attackers to misrepresent a malicious site's origin via a long hostname. The address bar truncates an overlong hostname from the right, preserving an attacker-controlled subdomain prefix while hiding the actual registrable domain. A user must open the crafted URL and rely on the displayed origin; the resulting deception can support credential theft, payment fraud, or session hijacking.
Summary
What happened
Address-bar spoofing in Zen Browser before 1.19.12b allows remote attackers to misrepresent a malicious site's origin via a long hostname. The address bar truncates an overlong hostname from the right, preserving an attacker-controlled subdomain prefix while hiding the actual registrable domain. A user must open the crafted URL and rely on the displayed origin; the resulting deception can support credential theft, payment fraud, or session hijacking.
The record
- CVE
- CVE-2026-44659
- Published
- May 11, 2026
- Updated
- May 11, 2026
- Vendor
- Zen Browser
- Product
- Zen Browser
- Classifications
- CWE-451, T1036
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- May 11, 2026CVE publishedPublication date reported by the CVE source.
- May 11, 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.
- Affected versionversion=< 1.19.12b
What conditions does exploitation require?
What is affected?
Published CVSS scores
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.
Weakness, pattern, technique
Public exploit references
- Long-subdomain address-bar spoofing reproductionproof of concept · demonstrated
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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