CVE-2026-29013

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

State
Published
Severity
8.8 High
Published
Apr 17, 2026
Updated
Jul 14, 2026
Reserved
Mar 3, 2026

Read the record on cve.org

Description

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.

Scores

CVSSScoreVectorSource
4.08.8 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:H/SC:N/SI:N/SA:NVulnCheck

Weaknesses

Affected Products

ProductVersions
libcoaplibcoap
  • before v4.3.5bAffected

References

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