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No exploitation reportedFix available

CVE-2020-3533

No exploitation reported by the sources we read.

  • Published2020-10-21
  • Fixed in6.6.1 · 6.5.0.5 · 6.4.0.10 · 6.3.0.6
  • WeaknessCWE-400

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

A vulnerability in the Simple Network Management Protocol (SNMP) input packet processor of Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause an affected device to restart unexpectedly. The vulnerability is due to a lack of sufficient memory management protections under heavy SNMP polling loads. An attacker could exploit this vulnerability by sending a high rate of SNMP requests to the SNMP daemon through the management interface on an affected device. A successful exploit could allow the attacker to cause the SNMP daemon process to consume a large amount of system memory over time, which could then lead to an unexpected device restart, causing a denial of service (DoS) condition. This vulnerability affects all versions of SNMP.

Timeline

dates in UTC
  1. 2020-10-2119:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2020-3533?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2020-3533?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Cisco secure firewall threat defense
BranchAffectedFixed in
6.6≥ 6.6.0, < 6.6.16.6.1
6.5≥ 6.5.0, < 6.5.0.56.5.0.5
6.4≥ 6.4.0, < 6.4.0.106.4.0.10
6.3< 6.3.0.66.3.0.6

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

  1. Update Cisco secure firewall threat defense to 6.6.1 · 6.5.0.5 · 6.4.0.10 · 6.3.0.6

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub

Sources

  • CISA-ADPSSVC decisionnone2024-11-13
  • OpenCVESSVC decisionnone—
  • CNACVSS 3.18.6read 2026-10-23
  • NVDCVSS 3.17.5read 2026-10-23
  • NVDCVSS 2.05read 2026-10-23
  • CNAweakness (CWE)CWE-400read 2026-10-23
  • NVDweakness (CWE)CWE-400read 2026-10-23
  • FIRST EPSSEPSS score1.8 %2026-10-23

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published
2020-10-21
Last Modified
2026-08-11
NVD status
Modified

Frequently asked questions

What is CVE-2020-3533?

A vulnerability in the Simple Network Management Protocol (SNMP) input packet processor of Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause an affected device to restart unexpectedly. The vulnerability is due to a lack of sufficient memory management protections under heavy SNMP polling loads. An attacker could exploit this vulnerability by sending a high rate of SNMP requests to the SNMP daemon through the management interface on an affected device. A successful exploit could allow the attacker to cause the SNMP daemon process to consume a large amount of system memory over time, which could then lead to an unexpected device restart, causing a denial of service (DoS) condition. This vulnerability affects all versions of SNMP.

Is CVE-2020-3533 actively exploited?

Active exploitation of CVE-2020-3533 has not been confirmed. Its EPSS score was 1.8% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2020-3533?

CVE-2020-3533 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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