CVE-2026-29013CWE-125

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

High · published April 17, 2026

CVSS v4.0
8.8
EPSS
1%
Percentile
43.4
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v4.0
8.8 · HIGH
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
EPSS
0.00522 · 43.4th percentile
Weakness
CWE-125 · Out-of-bounds Read
Published
2026-04-17T21:11Z
EPSS history
Timeline
  • 17 APR 21:11Z
    libcoap Out-of-Bounds Read in OSCORE CBOR Unwrap Handling
    cvelistv5