CVE-2020-26070

Cisco IOS XR Software for Cisco ASR 9000 Series Aggregation Services Routers Slow Path Forwarding Denial of Service Vulnerability

HIGH
8.6
CVSS Score
Published: November 12, 2020 at 02:05 AM UTC
Updated: June 17, 2026 at 03:07 AM UTC
12 products affected across 1 vendorIOS XrAsr 9010Asr 9904

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Severity
HIGH8.6
Exploit prediction
EPSS 2%
SSVC
No known exploit

Description

A vulnerability in the ingress packet processing function of Cisco IOS XR Software for Cisco ASR 9000 Series Aggregation Services Routers could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to improper resource allocation when an affected device processes network traffic in software switching mode (punted). An attacker could exploit this vulnerability by sending specific streams of Layer 2 or Layer 3 protocol data units (PDUs) to an affected device. A successful exploit could cause the affected device to run out of buffer resources, which could make the device unable to process or forward traffic, resulting in a DoS condition. The device would need to be restarted to regain functionality.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 6.7.27.1.0 ≤ v < 7.1.2
Affected range stops below 6.7.2, so it looks safe — our inference, not a vendor statement
Affected range stops below 7.1.2, so it looks safe — our inference, not a vendor statement
cisco-asr-9000v (environment) · cisco-asr-9001 (environment) · cisco-asr-9006 (environment) · cisco-asr-9010 (environment) · cisco-asr-9901 (environment) · cisco-asr-9903 (environment) · cisco-asr-9904 (environment) · cisco-asr-9906 (environment) · cisco-asr-9910 (environment) · cisco-asr-9912 (environment) · cisco-asr-9922 (environment)
All versions
All versions
All versions
All versions
All versions
All versions
All versions
All versions
All versions

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.6HIGHcisco
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
CHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-404

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