CVE-2026-6621 1024bit extend-deep index.js prototype pollution
Remote attackers can achieve code execution or privilege escalation via prototype pollution in the extend-deep library, which lacks active maintenance.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-6621?
CVE-2026-6621 is a medium-severity code injection vulnerability in 1024bit extend-deep, published on 20 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
A vulnerability was determined in 1024bit extend-deep up to 0.1.6. The impacted element is an unknown function of the file index.js. This manipulation of the argument __proto__ causes improperly controlled modification of object prototype attributes. Remote exploitation of the attack is possible. The exploit has been publicly disclosed and may be utilized. The code repository of the project has not been active for many years.
Which versions are affected by CVE-2026-6621?
How do I fix CVE-2026-6621?
No fix has been published for CVE-2026-6621 yet. Limit exposure of the affected software until one is available.
Upgrade, and never evaluate templates, expressions or code built from user input. More about Code injection.
Is CVE-2026-6621 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-6621 exists.
Sources
Also known as GHSA-vr46-pfqh-wpf8.