4.3

CVE-2021-1220: cisco cisco ios xe software Improper Input Validation

CVSS: 4.3v3.1MediumModified
Published 24-03-2021Last modified 17-09-2024

Vulnerability summary

CVE-2021-1220 is a medium (CVSS 4.3) Improper Input Validation vulnerability in cisco cisco ios xe software. EPSS estimates a 0.98% chance of exploitation in the next 30 days, higher than 61.5% of scored vulnerabilities.

Overall risk
17/100
0100
Low · default modelHow is this calculated?
CVSS score
4.3/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.98%
0%100%
Low · +0.03 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 24-03-2021
    PublishedVulnerability first disclosed.
  2. 17-09-2024
    Last modifiedVulnerability information updated.

Description

Multiple vulnerabilities in the web UI of Cisco IOS XE Software could allow an authenticated, remote attacker with read-only privileges to cause the web UI software to become unresponsive and consume vty line instances, resulting in a denial of service (DoS) condition. These vulnerabilities are due to insufficient error handling in the web UI. An attacker could exploit these vulnerabilities by sending crafted HTTP packets to an affected device. A successful exploit could allow the attacker to cause the web UI software to become unresponsive and consume all available vty lines, preventing new session establishment and resulting in a DoS condition. Manual intervention would be required to regain web UI and vty session functionality. Note: These vulnerabilities do not affect the console connection.

CVSS metrics

3 scores · 2 sources · 2 versions

EPSS trend

Probability

0.98%

Chance of exploitation in the next 30 days

Percentile

62%

Versus all other CVEs

30-day change

+0.03 pp

From 0.94% on 20-09-2026

20-09-202620-10-2026
EPSS score
0.98%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Cisco2 products
  • cisco ios xe softwaren/a
  • ios_xe3.15.1xbs | 3.15.2xbs | 16.11.1 | 16.11.1a | 16.11.1b | 16.11.1c | 16.11.1s | 16.11.2 | 16.12.1 | 16.12.1a | 16.12.1c | 16.12.1s | 16.12.1t | 16.12.1w | 16.12.1x | 16.12.1y | 16.12.1z | 16.12.2 | 16.12.2a | 16.12.2s | 16.12.2t | 16.12.3 | 16.12.3a | 16.12.3s | 16.12.4 | 16.12.4a | 17.1.1 | 17.1.1a | 17.1.1s | 17.1.1t | 17.1.2 | 17.2.1 | 17.2.1a | 17.2.1r | 17.2.1v

1 vendor · 2 products

References

1 links