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    CVE-2025-65496

    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.

    Published:Nov 24, 2025
    Last Modified:Dec 1, 2025
    EPS:Nov 24, 2025
    EPSS Score:0.00128
    CVSS Score:4.3

    Affected Products

    Vendor
    Libcoap
    Product
    Libcoap

    Exploits

    No exploit reference

    Common Weakness Enumeration

    CWE-476 NULL Pointer Dereference

    Common Attack Pattern Enumeration and Classification (CAPEC)

    No CAPEC recorded yet

    Related CVEs

    CVE-2026-29013 (CVSS 8.8) — libcoap contains out-of-bounds read vulnerabilities in OSCORE Appendix B.2 CBOR unwrap handling where get_byte…
    CVE-2025-34468 (CVSS 8.2) — libcoap versions up to and including 4.3.5, prior to commit 30db3ea, contain a stack-based buffer overflow in …
    CVE-2025-59391 (CVSS 6.5) — A memory disclosure vulnerability exists in libcoap's OSCORE configuration parser in libcoap before release-4.…
    CVE-2025-65501 (CVSS 4.3) — Null pointer dereference in coap_dtls_info_callback() in OISM libcoap 4.3.5 allows remote attackers to cause a…
    CVE-2025-65497 (CVSS 4.3) — NULL pointer dereference in coap_dtls_generate_cookie() in src/coap_openssl.c in OISM libcoap 4.3.5 allows rem…
    CVE-2025-65499 (CVSS 4.3) — Array index error in tls_verify_call_back() in src/coap_openssl.c in OISM libcoap 4.3.5 allows remote attacker…
    CVE-2025-65493 (CVSS 7.5) — NULL pointer dereference in src/coap_openssl.c in OISM libcoap 4.3.5 allows remote attackers to cause a denial…
    CVE-2025-65494 (CVSS 7.5) — NULL pointer dereference in get_san_or_cn_from_cert() in src/coap_openssl.c in OISM libcoap 4.3.5 allows remot…
    CVE-2025-65495 (CVSS 7.5) — Integer signedness error in tls_verify_call_back() in src/coap_openssl.c in OISM libcoap 4.3.5 allows remote a…
    CVE-2025-65498 (CVSS 4.3) — NULL pointer dereference in coap_dtls_generate_cookie() in src/coap_openssl.c in OISM libcoap 4.3.5 allows rem…

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High