CVE-2026-29013
CVE-2026-29013 is a critical-severity vulnerability in Libcoap with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-125.
Key facts
- Severity: Critical (CVSS 3.x base score 9.8)
- CVSS v4: 8.8
- EPSS exploit prediction: 0% (21st percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-23535
- Weakness: CWE-125
- Affected product: Libcoap
- Published:
- Last modified:
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.
Frequently asked questions
- What is CVE-2026-29013?
- 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.
- How severe is CVE-2026-29013?
- CVE-2026-29013 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
- Is CVE-2026-29013 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (21st percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2026-29013?
- CVE-2026-29013 affects Libcoap. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2026-29013?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
- Does CVE-2026-29013 have an EU (EUVD) identifier?
- Yes. CVE-2026-29013 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-23535.
- When was CVE-2026-29013 published?
- CVE-2026-29013 was published on 2026-04-17 and last updated on 2026-06-17.
References
Affected products (1)
- cpe:2.3:a:libcoap:libcoap:*:*:*:*:*:*:*:*
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