What is CVE-2025-65499?

CVE-2025-65499 is a medium-severity vulnerability in Libcoap, classified under Improper Validation of Array Index. CVSS score: 4.3/10. Published 2025-11-24.

How severe is CVE-2025-65499?

Medium severity. CVSS v3 base score is 4.3 out of 10.

Vulnerability in Libcoap

CVE-2025-65499

Array index error in tls_verify_call_back() in src/coap_openssl.c in OISM libcoap 4.3.5 allows remote attackers to cause a denial of service via a crafted DTLS handshake that triggers SSL_get_ex_data_X509_STORE_CTX_idx() to return -1.

EPSS: 0.003 (17.5th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L.

Affected products

Libcoap — versions 4.3.5
N/a — versions n/a

Weakness classification (CWE)

CWE-129 — Improper Validation of Array Index

References

cve@mitre.org (Issue Tracking)
cve@mitre.org (Patch, Issue Tracking)

Frequently asked questions

What is CVE-2025-65499?: CVE-2025-65499 is a medium-severity vulnerability in Libcoap, classified under Improper Validation of Array Index. CVSS score: 4.3/10. Published 2025-11-24.
How severe is CVE-2025-65499?: Medium severity. CVSS v3 base score is 4.3 out of 10.