In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.
Test your applicationsThere is no fixed version for Debian:11 libcoap2.
Note: Versions mentioned in the description apply only to the upstream libcoap2 package and not the libcoap2 package as distributed by Debian.
See How to fix? for Debian:11 relevant fixed versions and status.
Integer signedness error in tls_verify_call_back() in src/coap_openssl.c in OISM libcoap 4.3.5 allows remote attackers to cause a denial of service via a crafted TLS certificate that causes i2d_X509() to return -1 and be misused as a malloc() size parameter.