HarborGuard / CVE
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HIGHCVE-2026-29013Published Modified CNA VulnCheck

CVE-2026-29013: libcoap Out-of-Bounds Read in OSCORE CBOR Unwrap Handling

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.

Metrics

CVSS v4.0
8.8
Severity
HIGH
Fixed in
v4.3.5b
Affected Products
1

Fix available

v4.3.5b
Patch commits
Affected packages
  • libcoap / libcoap
    < v4.3.5b (from 0)
CVSS Vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:H/SC:N/SI:N/SA:N
References