Security Resilience

CVE-2020-3161

Cisco Ip Phone 8865 Firmware 10.3\(1\)es14 … 11.0\(5\)sr1

CISA KEVActive ExploitationEUVD ExploitedPublic PoC
Published
15 April 2020
Modified
28 October 2025
KEV Added
03 November 2021
Patch / advisory
CVSS Score v3.1 9.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.84 99.7th percentile
Risk Priority 97 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2020-3161 is a critical-severity Improper Input Validation (CWE-20) vulnerability in Cisco Ip Phone 8865 Firmware. Its CVSS base score is 9.8 (Critical).

Operationally, ranked in the top 0.3% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog; a public proof-of-concept is referenced.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

A vulnerability exists in the web server component of Cisco IP Phones due to improper input validation of HTTP requests, tracked as CWE-20. This flaw affects multiple models of Cisco IP Phones and carries a CVSS v3.1 score of 9.8, reflecting its critical severity and network-exploitable nature without authentication.

An unauthenticated remote attacker can exploit the issue by sending a specially crafted HTTP request to the device's web server. Successful exploitation grants the ability to execute arbitrary code with root privileges on the phone or trigger a reload that results in a denial-of-service condition.

The Cisco Security Advisory cisco-sa-voip-phones-rce-dos-rB6EeRXs and public proof-of-concept files on Packet Storm detail the remote code execution and denial-of-service vectors. CVE-2020-3161 is listed in CISA's Known Exploited Vulnerabilities Catalog, confirming observed in-the-wild exploitation.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

A vulnerability in the web server for Cisco IP Phones could allow an unauthenticated, remote attacker to execute code with root privileges or cause a reload of an affected IP phone, resulting in a denial of service (DoS) condition. The…

more

vulnerability is due to a lack of proper input validation of HTTP requests. An attacker could exploit this vulnerability by sending a crafted HTTP request to the web server of a targeted device. A successful exploit could allow the attacker to remotely execute code with root privileges or cause a reload of an affected IP phone, resulting in a DoS condition.

CWE(s)
KEV Date Added
03 November 2021

Related Threats

CVEs Like This One

CVE-2017-12319Same product: Cisco 8831both on KEV
CVE-2018-0125Same vendor: Ciscoboth on KEV
CVE-2009-2055Same vendor: Ciscoboth on KEV
CVE-2025-20393Same vendor: Ciscoboth on KEV
CVE-2017-3881Same vendor: Ciscoboth on KEV
CVE-2018-0159Same vendor: Ciscoboth on KEV
CVE-2017-12235Same vendor: Ciscoboth on KEV
CVE-2017-12234Same vendor: Ciscoboth on KEV
CVE-2017-12233Same vendor: Ciscoboth on KEV
CVE-2017-12240Same product: Cisco 8831both on KEV

Affected Assets

cisco
ip phone 8865 firmware
10.3\(1\)es14, 11.0\(1\), 11.0\(5\)sr1
cisco
ip phone 8851 firmware
10.3\(1\)es14, 11.0\(1\), 11.0\(5\)sr1
cisco
ip phone 7841 firmware
11.0\(1\)
cisco
ip phone 7821 firmware
11.0\(1\)
cisco
ip phone 8811 firmware
10.3\(1\)es14, 11.0\(1\), 11.0\(5\)sr1
cisco
ip phone 8861 firmware
10.3\(1\)es14, 11.0\(1\), 11.0\(5\)sr1
cisco
ip phone 8845 firmware
10.3\(1\)es14, 11.0\(1\), 11.0\(5\)sr1
cisco
ip phone 7861 firmware
11.0\(1\)
cisco
ip phone 8841 firmware
10.3\(1\)es14, 11.0\(1\), 11.0\(5\)sr1
cisco
ip phone 7811 firmware
11.0\(1\)
+3 more product configuration(s) — see NVD for full list

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.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

blocks

A.8.25 mandates security requirements, secure coding guidelines, checkpoints, testing (incl. code scans) and developer training in the SDLC, which reaches a slice of input validation defects but leaves the majority (incomplete enforcement, second-order inputs, parser differentials, post-validation canonicalization) unaddressed as in the SA-3 and A.8.28 anchors.

blocks

Mandating input controls that include integrity checks and input validation ensures that untrusted data is examined before use, blocking the root cause of many injection and malformed-data weaknesses.

blocks

Security-by-design principles explicitly call for data validation and sanitization at every layer, reducing the chance that malformed or malicious input will be processed without scrutiny.

prevents

Requiring language-specific secure coding standards, peer review, SAST and documented mitigation of common programming errors forces validation of all inputs before they are trusted.

finds

Testing against a defined set of requirements and using code review plus vulnerability scanning forces validation of inputs and handling of unanticipated conditions, reducing the chance that malformed data will be accepted.

Hardening callouts derived

DISA STIG baselines are authored against specific weaknesses. Where this CVE cites a broad weakness class, the mapping is not asserted at that abstraction (owner ruling, 2026-09-25: grade only at Base and below), so no rule is shown here rather than a rule shown against the wrong grain.

  • No fine-grained STIG row for CWE-20, a class-level weakness, and none of its children carries one either.

References