Cyber Resilience

CVE-2021-1220

Medium

Published: 24 March 2021

Published
24 March 2021
Modified
21 November 2024
KEV Added
Patch
CVSS Score v3.1 4.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
EPSS Score 0.0020 42.0th percentile
Risk Priority 9 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-1220 is a medium-severity Improper Input Validation (CWE-20) vulnerability in Cisco Ios Xe. Its CVSS base score is 4.3 (Medium).

Operationally, ranked at the 42.0th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability details

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…

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(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.

CWE(s)

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

cisco
ios xe
16.11.1, 16.11.1a, 16.11.1b, 16.11.1c, 16.11.1s

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-20

Security testing and developer training directly verify and enforce proper input validation, reducing exploitability of injection and malformed-data weaknesses.

addresses: CWE-20

Security testing and evaluation at multiple SDLC stages directly detects missing or flawed input validation, with the required remediation process ensuring fixes are applied.

addresses: CWE-20

Directly implements checks on information inputs to reject invalid data before processing.

addresses: CWE-20

Spam protection mechanisms perform filtering and detection on inbound/outbound messages, directly compensating for missing or weak input validation of unsolicited content.

References