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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- Low
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
8.8
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.
- Record
CVE-2026-29013- CVSS 4.0
- 8.8 High
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 - Weakness
- CWE-125
- Updated
- 2026-11-02
EUVDEUVD-2026-23535
8.8
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.
- Record
EUVD-2026-23535- CVSS 4.0
- 8.8 High
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 - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-4vrr-6f8v-98rf
8.8
libcoap contains out-of-bounds read vulnerabilities in OSCORE Appendix B.2 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 heap buffer overflow writes through integer wraparound in allocation size computation.
- Record
GHSA-4vrr-6f8v-98rf- CVSS 4.0
- 8.8 High
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-125
- Updated
- 2026-11-02
NVD
8.8
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.
- Record
CVE-2026-29013- CVSS 4.0
- 8.8 High
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-125
- Updated
- 2026-11-02
OSV
8.8
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.
- Record
CVE-2026-29013- CVSS 4.0
- 8.8 High
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 - Weakness
- CWE-125
- Updated
- 2026-11-02
OSVDEBIAN-CVE-2026-29013
9.8
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.
- Record
DEBIAN-CVE-2026-29013- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVUBUNTU-CVE-2026-29013
8.8
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.
- Record
UBUNTU-CVE-2026-29013- CVSS 4.0
- 8.8 High
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 - CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVopenSUSE-SU-2026:10592-1 No score
libcoap-devel-4.3.5b-1.1 on GA media
These are all security issues fixed in the libcoap-devel-4.3.5b-1.1 package on the GA media of openSUSE Tumbleweed.
- Record
openSUSE-SU-2026:10592-1- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
libcoap3Debian:12 |
All versions, plus listed versions 4.3.1-14.3.1-24.3.3-14.3.4-14.3.4-1.1 Show 5 moreShow less4.3.4-1.1~exp14.3.5-14.3.5-24.3.5-34.3.5-4 |
None known |
libcoap3Debian:13 |
before 4.3.4-1.1+deb13u3, plus listed versions 4.3.4-1.14.3.4-1.1+deb13u14.3.4-1.1+deb13u2 |
4.3.4-1.1+deb13u3 |
libcoap3Debian:14 |
before 4.3.5-3, plus listed versions 4.3.4-1.14.3.5-14.3.5-2 |
4.3.5-3 |
libcoapUbuntu:18.04:LTS |
All versions, plus listed versions 4.1.2-1 |
None known |
libcoap2Ubuntu:20.04:LTS |
All versions, plus listed versions 4.2.0-24.2.1-1 |
None known |
libcoap2Ubuntu:22.04:LTS |
All versions, plus listed versions 4.2.1-14.2.1-1build1 |
None known |
libcoap3Ubuntu:22.04:LTS |
All versions, plus listed versions 4.3.0-24.3.0-2build1 |
None known |
libcoap3Ubuntu:24.04:LTS |
All versions, plus listed versions 4.3.1-24.3.3-14.3.4-14.3.4-1.1build24.3.4-1.1build34.3.4-1.1build4 |
None known |
libcoap3Ubuntu:25.10 |
All versions, plus listed versions 4.3.4-1.1build4 |
None known |
libcoap3Ubuntu:26.10 |
All versions, plus listed versions 4.3.5-24.3.5-34.3.5-44.3.5-4ubuntu1 |
None known |
libcoap3Ubuntu:26.04:LTS |
All versions, plus listed versions 4.3.4-1.1build44.3.5-14.3.5-2 |
None known |
libcoapopenSUSE:Tumbleweed |
before 4.3.5b-1.1 | 4.3.5b-1.1 |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-29013 is a high vulnerability (CVSS 8.8) in Libcoap, published April 17, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.30%, the 22nd percentile. Fixed in libcoap3 4.3.4-1.1+deb13u3.
References
github.com/obgm/libcoap/commit/b7847c4dbb0dbee7c90b09a673d4cae256f03718
nvd.nist.gov/vuln/detail/CVE-2026-29013
vulncheck.com/advisories/libcoap-out-of-bounds-read-in-oscore-cbor-unwrap-handling
github.com/advisories/GHSA-4vrr-6f8v-98rf
github.com/CVEProject/cvelistV5/tree/main/cves/2026/29xxx/CVE-2026-29013.json
security-tracker.debian.org/tracker/CVE-2026-29013
ubuntu.com/security/CVE-2026-29013
cve.org/CVERecord?id=CVE-2026-29013
suse.com/security/cve/CVE-2026-29013