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Fencer Intel
medium 6.8

CVE-2021-40114 json

Multiple Cisco Products Snort Memory Leak Denial of Service Vulnerability

published 5y ago modified 2mo ago also EUVD-2021-27301

cvss
6.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
2.5%
EPSS 2.5% chance of exploitation in 30 days, percentile 84%
public exploits
0
none known

Summary

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.

Patch / fix

  • cisco secure_firewall_threat_defense 6.4.0.12, 6.6.3, 6.7.0.2
  • cisco unified_threat_defense 16.12.6, 17.3.4a, 17.4.2
  • snort snort 2.9.18
  • snort Alpine 3.24, Alpine 3.23, Alpine 3.22 +7 more 2.9.18-r0

alpine advisories ALPINE-CVE-2021-40114

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

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CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2y ago

Exploit prediction

2.47% chance of exploitation in the next 30 days, higher than 84% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 6.8 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 7.8 AV:N/AC:L/Au:N/C:N/I:N/A:C

Affected products

  • Cisco Cisco Firepower Threat Defense Software

Classification

Weakness
  • CWE-770 Allocation of Resources Without Limits or Throttling
  • CWE-401 Missing Release of Memory after Effective Lifetime

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.