CVE-2026-29013

CRITICAL

libcoap Out-of-Bounds Read in OSCORE CBOR Unwrap Handling

Title source: cna
STIX 2.1

Description

libcoap contains out-of-bounds read vulnerabilities in OSCORE Appendix B.2 CBOR unwrap handling where get_byte_inc() in src/oscore/oscore_cbor.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.

Scores

CVSS v3 9.8
EPSS 0.0030
EPSS Percentile 21.1%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CISA SSVC

Vulnrichment
Exploitation none
Automatable yes
Technical Impact partial

Details

CWE
CWE-125
Status published
Products (2)
libcoap/libcoap < 4.3.5b
libcoap/libcoap < v4.3.5b
Published Apr 17, 2026
Tracked Since Apr 18, 2026