Vulnerability in Cisco iOS Xe Software
CVE-2021-1616
A vulnerability in the H.323 application level gateway (ALG) used by the Network Address Translation (NAT) feature of Cisco IOS XE Software could allow an unauthenticated, remote attacker to bypass the ALG. This vulnerability is due to insufficient data validation of traffic that is traversing the ALG. An attacker could exploit this vulnerability by sending crafted traffic to a targeted device. A successful exploit could allow the attacker to bypass the ALG and open connections that should not be allowed to a remote device located behind the ALG. Note: This vulnerability has been publicly discussed as NAT Slipstreaming.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.7 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:N.
EPSS exploit prediction
EPSS: 0.012 (66.9th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 67th percentile — 66.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.012 · newest: 0.012 · change: 0.000
Affected products
Weakness classification (CWE)
Public proof-of-concept exploits
References
- tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxe-h3… (vendor-advisory, Vendor Advisory)
Frequently asked questions
- What is CVE-2021-1616?
- CVE-2021-1616 is a medium-severity vulnerability in Cisco iOS Xe Software, classified under Protection Mechanism Failure. CVSS score: 4.7/10. Published 2021-09-23.
- How severe is CVE-2021-1616?
- Medium severity. CVSS v3 base score is 4.7 out of 10.
- Is CVE-2021-1616 known to be exploited?
- 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.