What’s Vulnerable › Vulnerabilities

CVE-2026-19986: Adblock for Youtube Extension Event Listener contentscript.js updateDynamicRules improper authorization

• Severity: medium (CVSS 5.4 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-17 · updated 2026-08-20
• Weakness: CWE-266

Description

A weakness has been identified in Adblock for Youtube Extension up to 7.2.1 on Chrome. The impacted element is the function updateDynamicRules of the file contentscript.js of the component Event Listener. This manipulation of the argument yt-anti-adblock-detected causes improper authorization. It is possible to initiate the attack remotely. The exploit has been made available to the public and could be used for attacks. The vendor was contacted early about this disclosure but did not respond in any way.

Affected products

• Adblock for Youtube Extension: 7.2.0, 7.2.1

References

• https://github.com/xryj920/chrome_extensions/blob/main/AdBlock%20Ltd.%20Adblock%20for%20Youtube%207.2.1%20allows%20persistent%20disabling%20of%20ad%20blocking%20through%20an%20unauthenticated%20DOM%20event
• https://vuldb.com/cve/CVE-2026-19986
• https://vuldb.com/submit/873935
• https://vuldb.com/vuln/391190
• https://vuldb.com/vuln/391190/cti
• https://vuldb.com/submit/873935

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