Security Resilience

CVE-2024-20436

Memory Safety in Cisco Ios Xe 16.10.1 … 3.9.2s

Memory Safety
Published
25 September 2024
Modified
08 October 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 0.0086 58th percentile
Risk Priority 66 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-2024-20436 is a high-severity NULL Pointer Dereference (CWE-476) vulnerability in Cisco Ios Xe. Its CVSS base score is 8.6 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique OS Credential Dumping (T1003); ranked in the top 42% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SA-15 (Development Process, Standards, and Tools) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

A10:2025 Mishandling of Exceptional Conditions

EU & UK References

Vulnerability Data

A vulnerability in the HTTP Server feature of Cisco IOS XE Software when the Telephony Service feature is enabled could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is…

more

due to a null pointer dereference when accessing specific URLs. An attacker could exploit this vulnerability by sending crafted HTTP traffic to an affected device. A successful exploit could allow the attacker to cause the affected device to reload, causing a DoS condition on the affected device.

CWE(s)
CWE-476

Related Threats

MITRE ATT&CK Enterprise Techniques

T1003 OS Credential Dumping Credential Access
Adversaries may attempt to dump credentials to obtain account login and credential material, normally in the form of a hash or a clear text password.
attack.mitre.org →
T1003.007 Proc Filesystem Credential Access
Adversaries may gather credentials from the proc filesystem or `/proc`.
attack.mitre.org →
T1006 Direct Volume Access Stealth
Adversaries may directly access a volume to bypass file access controls and file system monitoring.
attack.mitre.org →
T1011 Exfiltration Over Other Network Medium Exfiltration
Adversaries may attempt to exfiltrate data over a different network medium than the command and control channel.
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 →
T1016 System Network Configuration Discovery Discovery
Adversaries may look for details about the network configuration and settings, such as IP and/or MAC addresses, of systems they access or through information discovery of remote systems.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2024-20312Same product: Cisco Ios Xe
CVE-2025-20338Same product: Cisco Ios Xe
CVE-2023-20067Same product: Cisco Ios Xe
CVE-2024-20437Same product: Cisco Ios Xe
CVE-2025-20195Same product: Cisco Ios Xe
CVE-2026-20104Same product: Cisco Ios Xe
CVE-2024-20480Same product: Cisco Ios Xe
CVE-2024-20314Same product: Cisco Ios Xe
CVE-2026-20124Same product: Cisco Ios Xe
CVE-2025-20312Same product: Cisco Ios Xe

Affected Assets

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

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

SA-11 Developer Testing and Evaluation good match

Developer testing and evaluation (including static analysis) directly finds null-dereference bugs before deployment.

SA-15 Development Process, Standards, and Tools partial match

Documented development standards and tools can enforce null-safety rules and safe pointer usage.

SA-8 Security and Privacy Engineering Principles partial match

Engineering principles can mandate defensive coding such as explicit null checks before dereference.

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.

PR.PS-06 partial match
blocks

Secure SDLC practices (static analysis, code review, safe coding standards) directly prevent NULL dereference bugs during development.

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.5.14 Information transfer partial match
removes
A.5.15 Access control partial match
removes
A.5.16 Identity management partial match
removes
A.5.17 Authentication information partial match
removes
A.5.18 Access rights partial match
removes
A.8.10 Information deletion partial match
removes

References