CVE-2017-20202 Web Developer for Chrome v0.4.9 Malicious Backdoor Supply Chain Compromise
A malicious backdoor in the Web Developer Chrome extension enabled code execution, credential theft, and ad fraud via a supply chain compromise.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2017-20202?
CVE-2017-20202 is a critical vulnerability in Web Developer for Chrome, published on 8 Oct 2025. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
Web Developer for Chrome v0.4.9 contained malicious code that generated a domain via a DGA and fetched a remote script. The fetched script conditionally loaded follow-on modules that performed extensive ad substitution and malvertising, displayed fake “repair” alerts that redirected users to affiliate programs, and attempted to harvest credentials when users logged in. Injected components enumerate common banner sizes for substitution, replace third-party ad calls, and redirect victim traffic to affiliate landing pages. Potential impacts include user-level code execution in the browser context, large-scale ad fraud and traffic hijacking, credential theft, and exposure to additional payloads delivered by the actor. The compromise was reported on by the maintainer of Web Developer for Chrome on August 2, 2017 and remediated in v0.5.0.
Weakness: CWE-506
Which versions are affected by CVE-2017-20202?
How do I fix CVE-2017-20202?
No fix has been published for CVE-2017-20202 yet. Limit exposure of the affected software until one is available.
Is CVE-2017-20202 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2017-20202 exists.
Sources
Also known as GHSA-vwvp-p3cc-rrj2.