CVE intelligence and bounded remediation

CVE-2021-1387 — Cisco Unified Computing System security vulnerability

High CVSS 8.6

A vulnerability in the network stack of Cisco NX-OS Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability exists because the software improperly releases resources when it processes certain IPv6 packets that are destined to an affected device. An attacker could exploit this vulnerability by sending multiple crafted IPv6 packets to an affected device. A successful exploit could cause the network stack to run out of available buffers, impairing operations of control plane and management plane protocols and resulting in a DoS condition. Manual intervention would be required to restore normal operations on the affected device. For more information about the impact of this vulnerability, see the Details section of this advisory.

Severity
High
CVSS
8.6 (3.1)
Published
2021-02-24
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-401

Affected products

  • cisco / unified_computing_system
  • cisco / nx-os / 7.0(0)n1(1)
  • cisco / nx-os / 7.0(1)n1(1)
  • cisco / nx-os / 7.0(2)n1(1)
  • cisco / nx-os / 7.0(3)n1(1)
  • cisco / nx-os / 7.0(4)n1(1)

Showing 6 representative product identities from 351 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Resource exhaustion and denial of service

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

Check exposure

  • Identify attacker-influenced work factors including input size, nesting, compression, fan-out, regex cost, allocation, recursion, retries, and connection lifetime.
  • Map per-request and shared CPU, memory, disk, descriptor, thread, queue, and downstream-service limits.
  • Determine whether authentication, tenancy, quotas, and rate controls apply before expensive processing begins.

Remediate safely

  • Bound input size, nesting, expansion, work, concurrency, queue depth, retries, and execution time before resource-intensive processing.
  • Release resources on every success, error, cancellation, and timeout path and use backpressure instead of unbounded buffering.
  • Update affected components and add small deterministic tests that assert resource ceilings rather than exhausting a host.

Authoritative sources

Complete CVE record and remediation plan

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