libcoap contains out-of-bounds read vulnerabilities in OSCORE Appendix B.2 CBOR unwrap handling where getbyteinc() in src/oscore/oscorecbor.c relies solely on assert() for bounds checking, which is removed in release builds compiled with NDEBUG. Attackers can send crafted CoAP requests with malformed OSCORE options or responses during OSCORE negotiation to trigger out-of-bounds reads during CBOR parsing and potentially cause out-of-bounds reads through integer wraparound in allocation size computation.

libcoap versions up to and including 4.3.5, prior to commit 30db3ea, contain a stack-based buffer overflow in address resolution when attacker-controlled hostname data is copied into a fixed 256-byte stack buffer without proper bounds checking. A remote attacker can trigger a crash and potentially achieve remote code execution depending on compiler options and runtime memory protections. Exploitation requires the proxy logic to be enabled (i.e., the proxy request handling code path in an application using libcoap).

A memory disclosure vulnerability exists in libcoap's OSCORE configuration parser in libcoap before release-4.3.5-patches. An out-of-bounds read may occur when parsing certain configuration values, allowing an attacker to infer or read memory beyond string boundaries in the .rodata section. This could potentially lead to information disclosure or denial of service.

NULL pointer dereference in coapdtlsgeneratecookie() in src/coapopenssl.c in OISM libcoap 4.3.5 allows remote attackers to cause a denial of service via a crafted DTLS handshake that triggers SSLgetSSLCTX() to return NULL.

NULL pointer dereference in src/coapopenssl.c in OISM libcoap 4.3.5 allows remote attackers to cause a denial of service via a crafted DTLS/TLS connection that triggers BIOgetdata() to return NULL.

Null pointer dereference in coapdtlsinfocallback() in OISM libcoap 4.3.5 allows remote attackers to cause a denial of service via a DTLS handshake where SSLgetappdata() returns NULL.

Integer signedness error in tlsverifycallback() in src/coapopenssl.c in OISM libcoap 4.3.5 allows remote attackers to cause a denial of service via a crafted TLS certificate that causes i2dX509() to return -1 and be misused as a malloc() size parameter.

Array index error in tlsverifycallback() in src/coapopenssl.c in OISM libcoap 4.3.5 allows remote attackers to cause a denial of service via a crafted DTLS handshake that triggers SSLgetexdataX509STORECTXidx() to return -1.

NULL pointer dereference in coapdtlsgeneratecookie() in src/coapopenssl.c in OISM libcoap 4.3.5 allows remote attackers to cause a denial of service via a crafted DTLS handshake that triggers SSLgetSSLCTX() to return NULL.

NULL pointer dereference in coapdtlsgeneratecookie() in src/coapopenssl.c in OISM libcoap 4.3.5 allows remote attackers to cause a denial of service via a crafted DTLS handshake that triggers SSLgetSSLCTX() to return NULL.

NULL pointer dereference in coapdtlsgeneratecookie() in src/coapopenssl.c in OISM libcoap 4.3.5 allows remote attackers to cause a denial of service via a crafted DTLS handshake that triggers SSLgetSSLCTX() to return NULL.

NULL pointer dereference in getsanorcnfromcert() in src/coapopenssl.c in OISM libcoap 4.3.5 allows remote attackers to cause a denial of service via a crafted X.509 certificate that causes skGENERALNAMEvalue() to return NULL.

A use-after-free vulnerability exists in the coapdeletepdulkd function within coappdu.c of the libcoap library. This issue occurs due to improper handling of memory after the freeing of a PDU object, leading to potential memory corruption or the possibility of executing arbitrary code. NOTE: this is disputed by the Supplier because it only occurs when an application uses libcoap incorrectly.

A NULL pointer dereference in libcoap v4.3.5-rc2 and below allows a remote attacker to cause a denial of service via the coaphandlerequestputblock function in src/coapblock.c.

An issue in coappdu.c in libcoap 4.3.4 allows attackers to cause undefined behavior via a sequence of messages leading to unsigned integer overflow.

A vulnerability was found in obgm libcoap 4.3.4. It has been rated as critical. Affected by this issue is the function getsplitentry of the file src/coaposcore.c of the component Configuration File Handler. The manipulation leads to stack-based buffer overflow. The attack may be launched remotely. The exploit has been disclosed to the public and may be used. It is recommended to apply a patch to fix this issue. VDB-252206 is the identifier assigned to this vulnerability.

Buffer Overflow vulnerability in coapsend function in libcoap library 4.3.1-103-g52cfd56 fixed in 4.3.1-120-ge242200 allows attackers to obtain sensitive information via malformed pdu.

libcoap 4.3.1 contains a buffer over-read via the function coapparseoscoreconfmem at coaposcore.c.