CVE-2026-29013

EUVD-2026-23535
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.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTPrimary
9.8 CRITICAL
NETWORK
LOW
NONE
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Base Score
CVSS 3.x
EPSS Score
Percentile: 21.81%
Affected Products (NVD)
VendorProductVersion
libcoaplibcoap
𝑥
< 4.3.5b
𝑥
= Vulnerable software versions
Debian logo
Debian Releases
Debian Product
Codename
libcoap3
bookworm
no-dsa
forky
4.3.5-4
fixed
sid
4.3.5-4
fixed
trixie
4.3.4-1.1+deb13u3
fixed
Ubuntu logo
Ubuntu Releases
Ubuntu Product
Codename
libcoap3
jammy
needs-triage
noble
needs-triage
questing
ignored
resolute
needs-triage
libcoap
bionic
needs-triage
jammy
dne
noble
dne
questing
dne
resolute
dne
libcoap2
focal
needs-triage
jammy
needs-triage
noble
dne
questing
dne
resolute
dne