CVE intelligence and bounded remediation

CVE-2021-1236 — Cisco Ios Xe security vulnerability

Medium CVSS 5.3

Multiple Cisco products are affected by a vulnerability in the Snort application detection engine that could allow an unauthenticated, remote attacker to bypass the configured policies on an affected system. The vulnerability is due to a flaw in the detection algorithm. An attacker could exploit this vulnerability by sending crafted packets that would flow through an affected system. A successful exploit could allow the attacker to bypass the configured policies and deliver a malicious payload to the protected network.

Severity
Medium
CVSS
5.3 (3.1)
Published
2021-01-13
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-670

Affected products

  • cisco / ios_xe
  • cisco / firepower_threat_defense
  • cisco / secure_firewall_management_center / 2.9.14.0
  • cisco / secure_firewall_management_center / 2.9.14.14
  • cisco / secure_firewall_management_center / 2.9.15
  • cisco / secure_firewall_management_center / 2.9.16

Showing 6 representative product identities from 8 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

General vulnerability remediation

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Confirm the affected component, deployment paths, reachable interfaces, and enabled features from inventories and configuration, without probing production destructively.
  • Compare the advisory's affected conditions with the repository lockfiles, build manifests, artifacts, and runtime inventory.
  • Identify data sensitivity, trust boundaries, and privilege level for every confirmed affected deployment.

Remediate safely

  • Apply a vendor-supported fix or remove the affected component or feature; record the selected change and its source in the repository.
  • Update direct and transitive dependency locks, generated artifacts, deployment manifests, and asset inventories together.
  • Add a regression test for the documented unsafe condition using inert inputs and preserve rollback instructions.

Authoritative sources

Complete CVE record and remediation plan

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