Cyber Resilience

CVE-2021-1402

High

Published: 29 April 2021

Published
29 April 2021
Modified
21 November 2024
KEV Added
Patch
CVSS Score v3.1 8.6 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
EPSS Score 0.0056 68.6th percentile
Risk Priority 18 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-1402 is a high-severity Improper Restriction of Operations within the Bounds of a Memory Buffer (CWE-119) vulnerability in Cisco Firepower Threat Defense. Its CVSS base score is 8.6 (High).

Operationally, ranked in the top 31.4% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability details

A vulnerability in the software-based SSL/TLS message handler of Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to trigger a reload of an affected device, resulting in a denial of service (DoS) condition. The vulnerability is…

more

due to insufficient validation of SSL/TLS messages when the device performs software-based SSL decryption. An attacker could exploit this vulnerability by sending a crafted SSL/TLS message through an affected device. SSL/TLS messages sent to an affected device do not trigger this vulnerability. A successful exploit could allow the attacker to cause a process to crash. This crash would then trigger a reload of the device. No manual intervention is needed to recover the device after the reload.

CWE(s)

Related Threats

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

Affected Assets

cisco
firepower threat defense
6.3.0 — 6.4.0 · 6.5.0 — 6.6.0

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 CWE-119

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

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

addresses: CWE-119

Managed runtimes used by platform-independent applications (e.g., JVM, CLR) enforce memory safety, preventing most buffer overflows that require direct memory manipulation.

addresses: CWE-20

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

addresses: CWE-119

Memory protections (e.g., W^X, ASLR) make exploitation of buffer-boundary violations far harder to turn into code execution.

addresses: CWE-119

Detects exploitation attempts that produce memory corruption, crashes, or anomalous behavior.

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