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

Status: published. Published: 2026-11-04. Updated: 2026-11-06.

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.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- NST Labs Tech / Nstbrowser: 1.2.0 (affected); 1.2.1 (affected). Source: CNA: VulDB

## Severity and prioritization

- CVSS 4.0: 5.3 (medium); 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; source: CNA: VulDB

- CVSS 3.1: 4.3 (medium); CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L/E:P/RL:X/RC:C; source: CNA: VulDB

- CVSS 3.0: 4.3 (medium); CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L/E:P/RL:X/RC:C; source: CNA: VulDB

- CVSS 2.0: 5 (medium); AV:N/AC:L/Au:N/C:N/I:N/A:P/E:POC/RL:ND/RC:C; source: CNA: VulDB

- CVSS 4.0: 2.1 (low); 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/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X; source: NVD: cna@vuldb.com

- CVSS 3.1: 4.3 (medium); CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L; source: NVD: cna@vuldb.com

- CVSS 2.0: 5 (medium); AV:N/AC:L/Au:N/C:N/I:N/A:P; source: NVD: cna@vuldb.com

- CISA KEV: No listing in collected sources

- EPSS: 0.32% as of 2026-11-05; percentile 25.02%

- SSVC: Not available

- Weaknesses: CWE-404

## Exploit evidence

- exploit: https://drive.google.com/drive/folders/1TzU1aHKabEHbMmSbqVR4HhxTAxKO6XII (CNA: VulDB)

## References

- https://vuldb.com/vuln/431086 (CNA: VulDB; vdb-entry, technical-description)

- https://vuldb.com/vuln/431086/cti (CNA: VulDB; signature, permissions-required)

- https://vuldb.com/cve/CVE-2026-122020 (CNA: VulDB; third-party-advisory)

- https://vuldb.com/submit/1024994 (CNA: VulDB; third-party-advisory)

- https://drive.google.com/drive/folders/1TzU1aHKabEHbMmSbqVR4HhxTAxKO6XII?usp=drive_link (CNA: VulDB; related)

- https://drive.google.com/drive/folders/1TzU1aHKabEHbMmSbqVR4HhxTAxKO6XII (CNA: VulDB; exploit)

- https://drive.google.com/drive/folders/1TzU1aHKabEHbMmSbqVR4HhxTAxKO6XII (cna@vuldb.com)

- https://drive.google.com/drive/folders/1TzU1aHKabEHbMmSbqVR4HhxTAxKO6XII?usp=drive_link (cna@vuldb.com)

- https://vuldb.com/cve/CVE-2026-122020 (cna@vuldb.com)

- https://vuldb.com/submit/1024994 (cna@vuldb.com)

- https://vuldb.com/vuln/431086 (cna@vuldb.com)

- https://vuldb.com/vuln/431086/cti (cna@vuldb.com)

## Provenance

- CNA: VulDB: https://www.cve.org/CVERecord?id=CVE-2026-122020; retrieved 2026-11-06; source updated 2026-11-06

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-122020; retrieved 2026-11-05; source updated 2026-11-04

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-122020; retrieved 2026-11-06; source updated Not reported

Revision: ab8be596ce10a86e6539f5636a6d164d13fd603a2339e0289ef2a3df738d1c47

Canonical: https://y2.dev/cve/CVE-2026-122020

## Agent and API access

Public CVE pages, Markdown, and JSON are free to read without an account or API key.

- Public catalog: https://y2.dev/cve/index.json. Follow nextCursor with the same search, filters, sort, and limit (1–100). A null cursor marks the end.

- WebMCP: search_cve_disclosures, get_cve_disclosure, get_cve_page_markdown, get_y2_cve_access. Available in compatible browsers.

- Cyber API: https://api.y2.dev/api/v2/cyber/cves and https://api.y2.dev/api/v2/cyber/cves/{cveId}.

- Y2 Pro or Elite: create a workspace API key with the intel:cyber scope and send Authorization: Bearer <Y2_API_KEY>. Setup: https://y2.dev/docs/api/create-key.

- x402: Pay per request without an account or API key. Omit Authorization, read the HTTP 402 PAYMENT-REQUIRED challenge, validate its current requirements, and retry with PAYMENT-SIGNATURE through an authorized payment client. These browser tools never make payments. Guide: https://y2.dev/docs/api/x402.

- OpenAPI: https://y2.dev/api/openapi.yaml. Agent access metadata: https://y2.dev/cve/agent.json.

Collected public records only. Check source status for coverage and freshness.