CVE-2026-29013
CRITICALlibcoap Out-of-Bounds Read in OSCORE CBOR Unwrap Handling
Title source: cnaDescription
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.
References (2)
Core 2
Core References
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