Paper/Archive/CVE-2026-29013

CVE-2026-29013

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

Description · from the CVE record

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.

Affected

ProductAffectedFixed inSource
libcoap< v4.3.5bv4.3.5bCNA

Scores by source

NVD9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
VulnCheck (CNA)8.8CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:H/SC:N/SI:N/SA:N
CISA ADPSSVCExploitation: none · Automatable: yes · Technical impact: partial

References

patchgithub.com/obgm/libcoap/commit/b7847c4dbb0dbee7c90b09a673d4cae256f03718