CVE-2026-44658Network attack vector

Trusted-tab navigation via unvalidated RSS item URLs

Published May 11, 2026 · Updated May 11, 2026

Improper input validation in Zen Browser before 1.19.12b allows remote attackers to create trusted tabs with non-web URLs via RSS feeds. The RSS provider copies each item link into item.url without enforcing the http: or https: scheme allowlist, and the live-folder manager passes it to gBrowser.addTrustedTab. Exploitation requires a user to add an attacker-controlled or compromised feed containing a recent non-web link and then restore or select the lazy tab; the documented consequence is attacker-chosen navigation, not code execution.

CVSS severity2.4
Low
EPSS probability0.16%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in Zen Browser before 1.19.12b allows remote attackers to create trusted tabs with non-web URLs via RSS feeds. The RSS provider copies each item link into item.url without enforcing the http: or https: scheme allowlist, and the live-folder manager passes it to gBrowser.addTrustedTab. Exploitation requires a user to add an attacker-controlled or compromised feed containing a recent non-web link and then restore or select the lazy tab; the documented consequence is attacker-chosen navigation, not code execution.

The record

CVE
CVE-2026-44658
Published
May 11, 2026
Updated
May 11, 2026
Vendor
Zen Browser
Product
Zen Browser
Classifications
Unavailable
Attack vector
network
Privileges
Unavailable

Timeline

How it unfolded

  1. May 11, 2026CVE publishedPublication date reported by the CVE source.
  2. 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.

  1. Affected versionversion=< 1.19.12b

What conditions does exploitation require?

Attack vectornetwork
Required privilegesUnavailable in this record.

What is affected?

Zen Browser · Zen Browserversion=< 1.19.12b

Published CVSS scores

2.4GitHubCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:N/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
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

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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