Cyber Resilience

CVE-2025-65499

Libcoap 4.3.5

Published
24 November 2025
Modified
01 December 2025
Patch / advisory
View advisory
CVSS Score v3.1 4.3
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
EPSS Score 0.0026 18th percentile
Risk Priority 36 floored blend · peak EPSS

Summary

CVE-2025-65499 is a medium-severity Improper Validation of Array Index (CWE-129) vulnerability in Libcoap Libcoap. Its CVSS base score is 4.3 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 18th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

OWASP Top 10 for Web (2025)

A05:2025 Injection

EU & UK References

Vulnerability Data

Array index error in tls_verify_call_back() in src/coap_openssl.c in OISM libcoap 4.3.5 allows remote attackers to cause a denial of service via a crafted DTLS handshake that triggers SSL_get_ex_data_X509_STORE_CTX_idx() to return -1.

CWE(s)
CWE-129

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 →
T1211 Exploitation for Stealth Stealth
Adversaries may exploit vulnerabilities to evade detection by hiding activity, suppressing logging, or operating within trusted or unmonitored components.
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-2023-30362Same product: Libcoap Libcoap
CVE-2023-35862Same product: Libcoap Libcoap
CVE-2026-29013Same product: Libcoap Libcoap
CVE-2025-59391Same product: Libcoap Libcoap
CVE-2024-0962Same product: Libcoap Libcoap
CVE-2025-34468Same product: Libcoap Libcoap
CVE-2025-65495Same product: Libcoap Libcoap
CVE-2025-65494Same product: Libcoap Libcoap
CVE-2025-65500Same product: Libcoap Libcoap
CVE-2025-65497Same product: Libcoap Libcoap

Affected Assets

libcoap
libcoap
4.3.5

Mitigating Controls

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 input validation and bounds checking that prevent improper array indexing.

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 out-of-bounds array access but does not prevent the weakness by itself.

A.8.25 Secure development life cycle partial match
prevents

Secure development lifecycle mandates input validation and bounds checking that directly prevents improper array indexing.

A.8.26 Application security requirements partial match
prevents

Application security requirements include validation of untrusted input used for indexing or addressing memory structures.

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

Secure architecture principles encourage defensive coding patterns that reduce index-related vulnerabilities.

A.8.28 Secure coding partial match
prevents

Secure coding standards explicitly require bounds checking and validation of array indices derived from untrusted data.

References