CVE-2025-65496
Medium · 4.3CVSS
4.3
EPSS
0.3%
Published
Nov 24, 2025
CISA due date
—
The record
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.
Affected packages
| Ecosystem | Package | Introduced | Fixed |
|---|---|---|---|
| openSUSE:Tumbleweed | libcoap | 0 | 4.3.5a-1.1 |
Related vulnerabilities
- CVE-2026-29013 libcoap contains out-of-bounds read vulnerabilities in OSCORE Appendix B.2 CBOR unwrap… Also affects libcoap
- CVE-2025-65497 NULL pointer dereference in coap_dtls_generate_cookie() in src/coap_openssl.c in OISM… Also affects libcoap
- CVE-2025-65501 Null pointer dereference in coap_dtls_info_callback() in OISM libcoap 4.3.5 allows remote… Also affects libcoap
- CVE-2025-65498 NULL pointer dereference in coap_dtls_generate_cookie() in src/coap_openssl.c in OISM… Also affects libcoap
- CVE-2025-65495 Integer signedness error in tls_verify_call_back() in src/coap_openssl.c in OISM libcoap… Also affects libcoap
- CVE-2025-65500 NULL pointer dereference in coap_dtls_generate_cookie() in src/coap_openssl.c in OISM… Also affects libcoap
- CVE-2025-65499 Array index error in tls_verify_call_back() in src/coap_openssl.c in OISM libcoap 4.3.5… Also affects libcoap
- CVE-2025-65493 NULL pointer dereference in src/coap_openssl.c in OISM libcoap 4.3.5 allows remote… Also affects libcoap