CVE-2025-65500

Medium

Description

NULL pointer dereference in coap_dtls_generate_cookie() 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_SSL_CTX() to return NULL.

SeverityMedium

CVSS4.3

Exploit probability—

ProductLibcoap

PublishedNov 24, 2025

First seenNov 24, 2025

Weakness typeCWE-476NULL pointer dereference

How to fix

Patches

github.com/obgm/libcoap/pull/1750

Affected products

Product	Affected versions	Fixed in
libcoap libcoap	4.3.5	—

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