Critical
libcoap, libcoap2 and 1 more products — security advisory
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.
- Products
- libcoap, libcoap2, libcoap3
- Affected versions
- 4.1.2-1, 4.2.0-2, 4.2.1-1, 4.2.1-1build1, 4.3.0-2, 4.3.0-2build1, 4.3.1-2, 4.3.3-1, 4.3.4-1, 4.3.4-1.1build2, 4.3.4-1.1build3, 4.3.4-1.1build4, 4.3.5-1, 4.3.5-2, 4.3.5-3, 4.3.5-4, 4.3.5-4ubuntu1
- Fixed versions
- Not specified
- CVEs
- CVE-2026-29013
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 02:58 UTC · Revision 1
Source evidence
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.
osv:UBUNTU-CVE-2026-29013
libcoap
Fixed versions: Not specified
libcoap2
Fixed versions: Not specified
libcoap2
Fixed versions: Not specified
libcoap3
Fixed versions: Not specified
libcoap3
Fixed versions: Not specified
libcoap3
Fixed versions: Not specified
libcoap3
Fixed versions: Not specified
libcoap3
Fixed versions: Not specified
Complete source record
{
"id": "26f1c586c4dc74c4f4665a77bcfdd8131bdf6f0d78c325819442499d6a768521",
"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-29013",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "UBUNTU-CVE-2026-29013",
"summary": "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.",
"evidence": "osv:UBUNTU-CVE-2026-29013",
"products": [
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{
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{
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],
"severity": "critical",
"structured": {
"id": "UBUNTU-CVE-2026-29013",
"aliases": [
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],
"metrics": [
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"type": "CVSS_V4",
"score": "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"
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"type": "CVSS_V3",
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"database_specific": {
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{
"binary_name": "libcoap-1-0-bin",
"binary_version": "4.1.2-1"
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"purl": "pkg:deb/ubuntu/libcoap2?arch=source&distro=focal",
"ecosystem": "Ubuntu:20.04:LTS"
},
"versions": [
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],
"database_specific": {
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},
"ecosystem_specific": {
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"binary_version": "4.2.1-1"
},
{
"binary_name": "libcoap2-bin",
"binary_version": "4.2.1-1"
}
]
}
},
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"package": {
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"ecosystem": "Ubuntu:22.04:LTS"
},
"versions": [
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"ecosystem_specific": {
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],
"modified": "2026-10-17T12:59:57.826602966Z",
"provider": "osv",
"upstream": [
"CVE-2026-29013"
],
"references": [
"https://ubuntu.com/security/CVE-2026-29013",
"https://www.cve.org/CVERecord?id=CVE-2026-29013"
]
},
"related_cves": [
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"security_relevant": true,
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"source_id": "core-osv",
"document_id": 360037,
"published_at": "2026-04-17T22:16:00+00:00"
}