CVE-2026-121661Microsoft Visual Studio Code incomplete denylist
CVE-2026-121661 is a incomplete denylist in Microsoft Visual Studio Code, rated high (7.8 on CVSS 3.1).
Why this priority: High severity, with no exploitation signal yet.
Published · Updated · NVD status: Awaiting Analysis
What it is
A list of forbidden inputs misses some, so a variant gets through.
How it is reached
An attacker can exploit it by someone who can already run code or sign in on the machine, without an account, but someone has to act first, such as opening a file or following a link.
What an attacker gains
A successful attack can read the data it protects, change data or behaviour and take it offline. In practice, this kind of flaw lets an attacker drive the component into behaviour its authors did not intend.
Is it being exploited?
There is no public report of exploitation yet.
What to do
- Upgrade Microsoft Visual Studio Code to 1.145.3 or later.
- Limit who can run code or sign in on the hosts that run it.
- Warn the people who use it, and filter files and links on the way in.
Description from NVD
Incomplete list of disallowed inputs in Visual Studio Code allows an unauthorized attacker to bypass a security feature locally.
What this means for your architecture.
A CVE names a product. Whether it matters depends on where that product sits in your systems: what reaches it, which trust boundary it guards and what it can reach once compromised. Veriom maps your components, their relationships and your trust boundaries from your code, cloud and delivery evidence, so you can see where a component like this sits. The radar itself does not look at your systems.
Components it touches
- Interfaces that accept external input. The flaw sits at the input boundary of the affected component.
Trust boundaries in play
- Host boundary. The attacker needs a foothold on the machine first; the flaw turns a small foothold into a bigger one.
- People who open files and links. Mail, chat and browsers are the delivery path.
- At the input boundary of the affected component. An attacker who crosses it can drive the component into behaviour its authors did not intend.
Questions to answer about your own systems
- Where does Microsoft Visual Studio Code run in your systems, and at which version?
- Which of those hosts also run code or users you do not fully trust?
- What can it reach once compromised: which data stores, secrets and services?
Sources
- CVE records and CVSS scores from the NVD CVE API. This product uses the NVD API but is not endorsed or certified by the NVD.
- Exploitation status from CISA’s Known Exploited Vulnerabilities catalog.
- Exploit likelihood from FIRST’s Exploit Prediction Scoring System (EPSS), refreshed daily.
- Explanations are written by Veriom from fixed templates over each record’s data, not by a person reviewing each CVE. Descriptions are quoted from the records as published.