CVE-2025-65495 — HIGH (7.5)

Vulnerability 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.

CVSS Score

7.5

HIGH

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

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality

NONE

Integrity

NONE

Availability

HIGH

Affected Products

Vendor	Product	Versions
Libcoap	Libcoap	4.3.5

Related Weaknesses (CWE)

CWE-195

References

https://github.com/obgm/libcoap/issues/1744Issue Tracking
https://github.com/obgm/libcoap/pull/1750Issue TrackingPatch

FAQ

What is CVE-2025-65495?

CVE-2025-65495 is a vulnerability with a CVSS score of 7.5 (HIGH). 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()...

How severe is CVE-2025-65495?

CVE-2025-65495 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2025-65495?

Check the references section above for vendor advisories and patch information. Affected products include: Libcoap Libcoap.