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Vulnerability record · CVE-2025-65500 · published 24 November 2025

CVE-2025-65500: Libcoap null pointer dereference vulnerability

Libcoap · Libcoap

NULL pointer dereference in coap_dtls_generate_cookie() 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_SSL_CTX() to return NULL.

4.3 CVSS 3.1 Medium EPSS 0.27% · top 83.5% CWE-476 · NULL pointer dereference
4.3CVSS 3.1 base score
0.27%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
2References
17 Jun 2026Last modified by NVD

Description

NULL pointer dereference in coap_dtls_generate_cookie() 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_SSL_CTX() to return NULL.

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/obgm/libcoap/issues/1746 Issue Tracking
https://github.com/obgm/libcoap/pull/1750 Issue TrackingPatch

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2025-65500), CISA KEV, FIRST EPSS (scores of 2026-09-29). This page is refreshed as NVD updates the record.