Security readout for executives and security teams
Plain-English summary
This flaw can make affected Snort-based Cisco security devices run out of memory while handling ICMP traffic. A remote unauthenticated attacker could trigger a denial of service, potentially causing a device reload and interrupting security inspection or network availability.
Executive priority
Treat as a moderate availability risk for perimeter or inline security infrastructure. Prioritize environments where affected devices sit on critical traffic paths, because a device reload can reduce inspection capacity or disrupt network services.
Technical view
CVE-2021-40114 is improper memory resource management in the Snort detection engine during ICMP packet processing. The provided CVSS v3.1 score is 6.8, with network attack vector, high complexity, no privileges, no user interaction, and high availability impact.
Likely exposure
Exposure is most relevant where affected Cisco products using Snort inspection, including Cisco Firepower Threat Defense Software, process untrusted ICMP traffic. Debian Snort security updates are also referenced. The bundle does not provide exact affected version ranges.
Exploitation context
The bundle says exploitation requires sending a series of ICMP packets through an affected device, but attack complexity is high. CISA KEV status is false, and no cited source in the bundle states active exploitation.
Researcher notes
Evidence supports a remote unauthenticated DoS condition caused by memory leakage during ICMP processing in Snort. Public source details in the bundle are limited to impact, root cause class, and vendor update references; version-specific exposure must be confirmed from vendor advisories.
Mitigation direction
- Review the Cisco advisory for affected product and fixed-release guidance.
- Apply relevant Cisco software updates where product and version match.
- For Debian Snort deployments, apply the referenced Debian security updates.
- Limit unnecessary ICMP exposure through affected inspection paths where operationally feasible.
- Monitor vendor advisories for version-specific remediation details.
Validation and detection
- Inventory Cisco products using Snort inspection, especially Firepower Threat Defense Software.
- Confirm installed versions against Cisco advisory applicability and fixed-release tables.
- Identify Debian systems with Snort packages and verify security update status.
- Review device logs for reloads, memory exhaustion, or ICMP-related instability.
- Confirm monitoring alerts cover security appliance reloads and availability loss.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-770: Exact CWE lookup
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Open ATT&CK lookupCVE-2021-40114 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 6.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H2.24Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
6.8MediumVector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H
Source materials
- CVE List V5 sourceCVE List V5
- 20211027 Multiple Cisco Products Snort Memory Leak Denial of Service VulnerabilityCVE reference · vendor-advisory
- [debian-lts-announce] 20230210 [SECURITY] [DLA 3317-1] snort security updateCVE reference · mailing-list
- DSA-5354CVE reference · vendor-advisory
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Allocation of Resources Without Limits or Throttling
Allocation of Resources Without Limits or Throttling represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.