Out-of-bounds Read Affecting libcoap3 package, versions <4.3.5-3


Severity

Recommended
0.0
critical
0
10

Snyk's Security Team recommends NVD's CVSS assessment. Learn more

Threat Intelligence

EPSS
0.52% (42nd percentile)

Do your applications use this vulnerable package?

In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.

Test your applications
  • Snyk IDSNYK-DEBIANUNSTABLE-LIBCOAP3-16104641
  • published19 Apr 2026
  • disclosed17 Apr 2026

Introduced: 17 Apr 2026

CVE-2026-29013  (opens in a new tab)
CWE-125  (opens in a new tab)

How to fix?

Upgrade Debian:unstable libcoap3 to version 4.3.5-3 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream libcoap3 package and not the libcoap3 package as distributed by Debian. See How to fix? for Debian:unstable relevant fixed versions and status.

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.

CVSS Base Scores

version 3.1