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 with a crafted handshake. During cookie generation in src/coap_openssl.c, coap_dtls_generate_cookie() passes the unchecked NULL result of SSL_get_SSL_CTX() into subsequent OpenSSL processing. The path requires an OpenSSL-backed DTLS endpoint to process the malicious handshake, and the resulting process crash interrupts the hosted CoAP service.
Summary
What happened
NULL pointer dereference in OISM libcoap 4.3.5 allows remote attackers to crash a DTLS-enabled service with a crafted handshake. During cookie generation in src/coap_openssl.c, coap_dtls_generate_cookie() passes the unchecked NULL result of SSL_get_SSL_CTX() into subsequent OpenSSL processing. The path requires an OpenSSL-backed DTLS endpoint to process the malicious handshake, and the resulting process crash interrupts the hosted CoAP service.
The record
- CVE
- CVE-2025-65498
- Published
- Nov 24, 2025
- Updated
- Nov 24, 2025
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Nov 24, 2025CVE publishedPublication date reported by the CVE source.
- Nov 24, 2025Record updatedLatest update available in the CVE record.
Exploitability
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Attacks
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Technologies
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