CVE-2021-1624: Cisco IOS XE Software Rate Limiting Network Address Translation Denial of Service Vulnerability
Vulnerability summary
CVE-2021-1624 is a high (CVSS 8.6) Resource Management Errors vulnerability in cisco cisco ios xe software. EPSS estimates a 1.33% chance of exploitation in the next 30 days, higher than 70.7% of scored vulnerabilities.
Timeline
- 23-09-2021PublishedVulnerability first disclosed.
- 07-11-2024Last modifiedVulnerability information updated.
Description
A vulnerability in the Rate Limiting Network Address Translation (NAT) feature of Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause high CPU utilization in the Cisco QuantumFlow Processor of an affected device, resulting in a denial of service (DoS) condition. This vulnerability is due to mishandling of the rate limiting feature within the QuantumFlow Processor. An attacker could exploit this vulnerability by sending large amounts of traffic that would be subject to NAT and rate limiting through an affected device. A successful exploit could allow the attacker to cause the QuantumFlow Processor utilization to reach 100 percent on the affected device, resulting in a DoS condition.
CVSS metrics
3 scores · 2 sources · 2 versions- NVDNIST8.6HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
EPSS trend
Probability
1.33%
Chance of exploitation in the next 30 days
Percentile
71%
Versus all other CVEs
30-day change
No change 0.00 pp
From 1.33% on 22-09-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Cisco2 products
- cisco ios xe softwaren/a
- ios_xe≤ 17.3.3
1 vendor · 2 products
References
1 links- tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ratenat-pYVLA7wMVendor AdvisoryX Refsource CISCO