CVE-2025-65496Network attack vector

Remote service crash via unchecked SSL context

Published Nov 24, 2025 · Updated Nov 24, 2025

NULL pointer dereference in OISM libcoap 4.3.5 allows remote attackers to crash a DTLS-enabled service via a crafted handshake. In coap_dtls_generate_cookie() in src/coap_openssl.c, an unchecked NULL result from SSL_get_SSL_CTX() is passed to SSL_CTX_get_app_data(), which dereferences the invalid context. The affected path requires a server built with DTLS and the OpenSSL backend, and triggering it terminates the serving process without exposing or modifying data.

CVSS severity4.3
Medium
EPSS probability0.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

NULL pointer dereference in OISM libcoap 4.3.5 allows remote attackers to crash a DTLS-enabled service via a crafted handshake. In coap_dtls_generate_cookie() in src/coap_openssl.c, an unchecked NULL result from SSL_get_SSL_CTX() is passed to SSL_CTX_get_app_data(), which dereferences the invalid context. The affected path requires a server built with DTLS and the OpenSSL backend, and triggering it terminates the serving process without exposing or modifying data.

The record

CVE
CVE-2025-65496
Published
Nov 24, 2025
Updated
Nov 24, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-476, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 24, 2025CVE publishedPublication date reported by the CVE source.
  2. Nov 24, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

4.3CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo