Security Resilience

CVE-2023-20187

Cisco Ios Xe 16.10.1 … 3.9.2s

Published
27 September 2023
Modified
21 November 2024
Patch / advisory
View advisory
CVSS Score v3.1 8.6
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
EPSS Score 0.0088 58th percentile
Risk Priority 63 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-2023-20187 is a high-severity Use of Out-of-range Pointer Offset (CWE-823) vulnerability in Cisco Ios Xe. Its CVSS base score is 8.6 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Data Obfuscation (T1001); ranked in the top 42% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability Data

A vulnerability in the Multicast Leaf Recycle Elimination (mLRE) feature of Cisco IOS XE Software for Cisco ASR 1000 Series Aggregation Services Routers could allow an unauthenticated, remote attacker to cause the affected device to reload, resulting in a denial…

more

of service (DoS) condition. This vulnerability is due to incorrect handling of certain IPv6 multicast packets when they are fanned out more than seven times on an affected device. An attacker could exploit this vulnerability by sending a specific IPv6 multicast or IPv6 multicast VPN (MVPNv6) packet through the affected device. A successful exploit could allow the attacker to cause a reload of the affected device, resulting in a DoS condition.

CWE(s)
CWE-823NVD-CWE-noinfo

Related Threats

MITRE ATT&CK Enterprise Techniques

T1001 Data Obfuscation Command And Control
Adversaries may obfuscate command and control traffic to make it more difficult to detect.
attack.mitre.org →
T1001.001 Junk Data Command And Control
Adversaries may add junk data to protocols used for command and control to make detection more difficult.
attack.mitre.org →
T1003.002 Security Account Manager Credential Access
Adversaries may attempt to extract credential material from the Security Account Manager (SAM) database either through in-memory techniques or through the Windows Registry where the SAM database is stored.
attack.mitre.org →
T1003.008 /etc/passwd and /etc/shadow Credential Access
Adversaries may attempt to dump the contents of <code>/etc/passwd</code> and <code>/etc/shadow</code> to enable offline password cracking.
attack.mitre.org →
T1008 Fallback Channels Command And Control
Adversaries may use fallback or alternate communication channels if the primary channel is compromised or inaccessible in order to maintain reliable command and control and to avoid data transfer thresholds.
attack.mitre.org →
T1012 Query Registry Discovery
Adversaries may interact with the Windows Registry to gather information about the system, configuration, and installed software.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-20022Same vendor: Cisco
CVE-2026-20104Same product: Cisco Ios Xe
CVE-2025-20155Same product: Cisco Ios Xe
CVE-2024-20306Same product: Cisco Ios Xe
CVE-2025-20315Same product: Cisco Ios Xe
CVE-2025-20202Same product: Cisco Ios Xe
CVE-2024-20313Same product: Cisco Ios Xe
CVE-2025-20174Same product: Cisco Ios Xe
CVE-2025-20169Same product: Cisco Ios Xe
CVE-2025-20170Same product: Cisco Ios Xe

Affected Assets

cisco
ios xe
16.10.1, 16.10.1a, 16.10.1e, 16.10.1s, 16.10.2

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)
  • 1 hardening rule · 1 OS baseline
Validate
Prove the fix (OWASP ASVS)
  • V1.4.1

Mitigating Controls (NIST CSF 2.0) AI

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

ID.RA-01 partial match
blocks

SAST/DAST tools used for vulnerability identification can surface this class of coding defect.

PR.PS-06 partial match
blocks

Secure SDLC practices directly require bounds-checked pointer arithmetic and static analysis to prevent out-of-range offsets.

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.

A.5.16 Identity management partial match
removes
A.8.25 Secure development life cycle partial match
blocks

Secure SDLC mandates input validation and bounds checking that can prevent out-of-range pointer offsets.

A.8.26 Application security requirements partial match
blocks

A.8.26 only requires that security requirements (including resilience against buffer overflows or SQL injections) be identified and specified during development or acquisition; it does not itself enforce, implement, or prevent out-of-range pointer arithmetic in the resulting application.

A.8.27 Secure system architecture and engineering principles partial match
removes
A.8.28 Secure coding partial match
prevents

Secure coding standards directly forbid unsafe pointer arithmetic and require bounds checks.

A.8.29 Security testing in development and acceptance partial match
finds

Security testing can detect out-of-range pointer offsets before release.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (higher-evidence rows only; rows rated `none` are excluded).

Windows 10 (1 rule)
  • V-220726 Data Execution Prevention (DEP) must be configured to at least OptOut. blocks CWE-823

References