Cyber Resilience

CVE-2026-20052

Memory Safety in Cisco Secure Firewall Threat Defense 7.4.0 … 7.6.0

Memory Safety
Published
04 March 2026
Modified
20 August 2026
Patch / advisory
View advisory
CVSS Score v3.1 5.8
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:L
EPSS Score 0.0041 34th percentile
Risk Priority 46 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-2026-20052 is a medium-severity Access of Memory Location After End of Buffer (CWE-788) vulnerability in Cisco Secure Firewall Threat Defense. Its CVSS base score is 5.8 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 34th percentile by exploit likelihood (below the median); 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-8 (Security and Privacy Engineering Principles) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

A vulnerability in the memory management handling for the Snort 3 Detection Engine of Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to restart. This vulnerability is due…

more

to a logic error in memory management when a device is performing Snort 3 SSL packet inspection. An attacker could exploit this vulnerability by sending crafted SSL packets through an established connection to be parsed by the Snort 3 Detection Engine. A successful exploit could allow the attacker to cause a denial of service (DoS) condition when the Snort 3 Detection Engine unexpectedly restarts.

CWE(s)
CWE-788

Related Threats

MITRE ATT&CK Enterprise Techniques

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
attack.mitre.org →
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
attack.mitre.org →
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
attack.mitre.org →
T1212 Exploitation for Credential Access Credential Access
Adversaries may exploit software vulnerabilities in an attempt to collect credentials.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2024-20402Same product: Cisco Secure Firewall Threat Defense
CVE-2024-20431Same product: Cisco Secure Firewall Threat Defense
CVE-2023-20270Same product: Cisco Secure Firewall Threat Defense
CVE-2026-20017Same product: Cisco Secure Firewall Threat Defense
CVE-2024-20330Same product: Cisco Secure Firewall Threat Defense
CVE-2026-20050Same product: Cisco Secure Firewall Threat Defense
CVE-2023-20267Same product: Cisco Secure Firewall Threat Defense
CVE-2026-20007Same product: Cisco Secure Firewall Threat Defense
CVE-2024-20261Same product: Cisco Secure Firewall Threat Defense
CVE-2024-20407Same product: Cisco Secure Firewall Threat Defense

Affected Assets

cisco
secure firewall threat defense
7.4.0, 7.4.1, 7.4.1.1, 7.4.2, 7.4.2.1

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V1.4.1

Mitigating Controls (NIST 800-53 r5) AI

SA-11 Developer Testing and Evaluation good match

Developer testing and evaluation can discover buffer-end violations through static analysis, fuzzing, or dynamic bounds checks.

SA-8 Security and Privacy Engineering Principles partial match

Security engineering principles require bounds checking, safe arithmetic, and language choices that structurally eliminate post-end buffer accesses.

SI-10 Information Input Validation partial match

Input validation enforces bounds on lengths and indices before buffer operations, stopping out-of-bounds accesses after the end of the buffer.

SI-16 Memory Protection partial match

Memory protection mechanisms limit the effects of post-end buffer accesses by blocking unauthorized code execution or data corruption.

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 mostly match
prevents

Secure SDLC practices directly require bounds checking and input validation that prevent out-of-bounds buffer accesses.

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.8.29 Security testing in development and acceptance mostly match
finds

Security testing in development can detect buffer-overrun defects before release.

A.8.25 Secure development life cycle partial match
prevents

Secure development life cycle includes buffer-handling practices that reduce out-of-bounds accesses.

A.8.26 Application security requirements partial match
prevents

Application security requirements can mandate bounds checking and safe memory APIs.

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

Secure architecture principles discourage unsafe pointer arithmetic and unbounded buffers.

A.8.28 Secure coding partial match
prevents

Secure coding standards directly forbid writing or reading past buffer ends.

References