CVE-2025-65495

High

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.

SeverityHigh

CVSS7.5

Exploit probability—

ProductLibcoap

PublishedNov 24, 2025

First seenNov 24, 2025

Weakness typeCWE-195CWE-195

How to fix

Patches

github.com/obgm/libcoap/pull/1750

Affected products

Product	Affected versions	Fixed in
libcoap libcoap	4.3.5	—

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