CVE-2025-65495

Published: Nov 24, 2025Modified: Jun 17, 2026

7.5

Vector

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

Exploitability: 3.9 / Impact: 3.6

Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0 (Secondary)

Description

Integer signedness 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 TLS certificate that causes i2d_X509() to return -1 and be misused as a malloc() size parameter.

Affected (1)

Products: Libcoap: Libcoap

1 product

Configuration A

1 vulnerable

Vulnerable Software	Affected Versions
Libcoap Libcoap	Version 4.3.5

Related CWEs

Signed to Unsigned Conversion Error

The product uses a signed primitive and performs a cast to an unsigned primitive, which can produce an unexpected value if the value of the signed primitive can not be represented using an unsigned primitive.

References (2)

https://github.com/obgm/libcoap/issues/1744

Source: cve@mitre.org

Issue Tracking

https://github.com/obgm/libcoap/pull/1750

Source: cve@mitre.org

Issue TrackingPatch

Timeline

No history available yet.