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No exploitation reportedFix available

CVE-2021-40114

No exploitation reported by the sources we read.

  • Published2021-10-27
  • WeaknessCWE-401 · CWE-770

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

Multiple Cisco products are affected by a vulnerability in the way the Snort detection engine processes ICMP traffic that could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to improper memory resource management while the Snort detection engine is processing ICMP packets. An attacker could exploit this vulnerability by sending a series of ICMP packets through an affected device. A successful exploit could allow the attacker to exhaust resources on the affected device, causing the device to reload.

Timeline

dates in UTC
  1. 2021-10-2719:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 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-2021-40114?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-40114?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 management center
BranchAffectedFixed in
2.9= 2.9.14.0no fix published
2.9= 2.9.15no fix published
2.9= 2.9.16no fix published
2.9= 2.9.17no fix published
Cisco secure firewall threat defense
BranchAffectedFixed in
6.7≥ 6.7.0, < 6.7.0.26.7.0.2
6.x≥ 6.5.0, < 6.6.36.6.3
6.4< 6.4.0.126.4.0.12
Cisco unified threat defense
BranchAffectedFixed in
17.4≥ 17.4, < 17.4.217.4.2
17.3≥ 17.3, < 17.3.4a17.3.4a
16.12≥ 16.12, < 16.12.616.12.6

1 more product in the sources.

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

Fix

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 decisionnone2024-11-07
  • OpenCVESSVC decisionnone—
  • CNACVSS 3.16.8read 2026-10-23
  • NVDCVSS 3.17.5read 2026-10-23
  • NVDCVSS 2.07.8read 2026-10-23
  • CNAweakness (CWE)CWE-770read 2026-10-23
  • NVDweakness (CWE)CWE-401read 2026-10-23
  • FIRST EPSSEPSS score2.5 %2026-10-22

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
2021-10-27
Last Modified
2026-08-11
NVD status
Modified

Frequently asked questions

What is CVE-2021-40114?

Multiple Cisco products are affected by a vulnerability in the way the Snort detection engine processes ICMP traffic that could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to improper memory resource management while the Snort detection engine is processing ICMP packets. An attacker could exploit this vulnerability by sending a series of ICMP packets through an affected device. A successful exploit could allow the attacker to exhaust resources on the affected device, causing the device to reload.

Is CVE-2021-40114 actively exploited?

Active exploitation of CVE-2021-40114 has not been confirmed. Its EPSS score was 2.5% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-40114?

CVE-2021-40114 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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