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Actively exploited

CVE-2020-5735 Amcrest Cameras and NVR Stack-based Buffer Overflow Vulnerability

Amcrest cameras and NVR contain a stack-based buffer overflow vulnerability through port 37777 that allows an unauthenticated, remote attacker to crash the device and possibly execute code.

From the CISA KEV catalogue version 2026.11.06, with Cybergen analysis. Updated 6 Nov 2026.

Our Assessment

Should You Worry?

Patch urgentlyCybergen assessment
  • CISA confirmed exploitation in the wild and added it to the Known Exploited Vulnerabilities catalogue on 3 Nov 2021.
  • Rated High severity (CVSS 8.8, scored by CISA).
  • It has been in the catalogue for 1,829 days. Systems still unpatched now have almost certainly been scanned for it.
The Vulnerability

What It Is

Amcrest cameras and NVR are vulnerable to a stack-based buffer overflow over port 37777. An authenticated remote attacker can abuse this issue to crash the device and possibly execute arbitrary code.

Affected Versions

ProductVersions
Amcrestbefore 2.623.00AC004.0.R.200316, 2.420.AC00.18.R.20200217, 2.800.00AC000.0.R.200330, 2.800.0000000.6.R.200314.bin, 2.622.00AC000.0.R.200320.bin, and 4.000.00AC000.0.R.200218

From the public CVE record, as supplied by the vendor. Always confirm against the vendor advisory.

From Watch to Action

What To Do Now

  1. 1

    Find it

    Search your asset inventory and external attack surface for Amcrest Cameras and Network Video Recorder (NVR). Include cloud images, appliances and anything a supplier runs for you.

    Attack Surface Management
  2. 2

    Fix it

    Apply updates per vendor instructions.

    Vulnerability Management
  3. 3

    Hunt for compromise

    If an affected system was reachable before you patched, assume it may have been hit. Check logs, new accounts, web shells and outbound connections from the date of exposure.

    Incident Response
  4. 4

    Prove it is fixed

    Rescan or test the system after patching. Upgrades that fail silently and forgotten secondary instances are common.

    Penetration Testing

Vendor Advisories

Regulation

The Compliance Clock

Cyber EssentialsRated high, so if it affects devices in your Cyber Essentials scope, the update must be installed within 14 days of the vendor releasing it.NIS2If exploitation causes a significant incident, essential and important entities owe their CSIRT an early warning within 24 hours and a notification within 72 hours.DORAFinancial entities must classify ICT incidents and send an initial notification for a major incident within strict deadlines, with exploited flaws a common cause.US federal (BOD 22-01)Federal civilian agencies had until 3 May 2022 to remediate. A sensible benchmark for everyone else.

General guidance, not legal advice. Your obligations depend on your sector, scope and jurisdiction.

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Evidence

Sources

  1. CISA Known Exploited Vulnerabilities catalogue
  2. NVD: CVE-2020-5735
  3. CVE record: CVE-2020-5735
  4. FIRST EPSS
  5. tenable.com/security/research/tra-2020-20
  6. packetstormsecurity.com/files/157164/Amcrest-Dahua-NVR-Camera-IP2M-841-Denial-Of-Service.html