obgm libcoap 4.3.5 DTLS src/coap_openssl.c coap_dtls_generate_cookie null pointer dereference

CVSS Meta Temp Score
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CTI Interest Score
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5.1$0-$5k0.00

Summaryinfo

A vulnerability described as problematic has been identified in obgm libcoap 4.3.5. This vulnerability affects the function coap_dtls_generate_cookie of the file src/coap_openssl.c of the component DTLS Handler. Such manipulation leads to null pointer dereference. This vulnerability is referenced as CVE-2025-65498. It is possible to launch the attack remotely. No exploit is available.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in obgm libcoap 4.3.5. Affected by this issue is the function coap_dtls_generate_cookie of the file src/coap_openssl.c of the component DTLS Handler. The manipulation with an unknown input leads to a null pointer dereference vulnerability. Using CWE to declare the problem leads to CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. Impacted is availability. CVE summarizes:

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.

The advisory is shared for download at github.com. This vulnerability is handled as CVE-2025-65498 since 11/18/2025. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. There are known technical details, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 276675 (Linux Distros Unpatched Vulnerability : CVE-2025-65498), which helps to determine the existence of the flaw in a target environment.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at Tenable (276675). Once again VulDB remains the best source for vulnerability data.

Productinfo

Vendor

Name

Version

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.3
VulDB Meta Temp Score: 5.1

VulDB Base Score: 5.3
VulDB Temp Score: 5.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Null pointer dereference
CWE: CWE-476 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 276675
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2025-65498

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

11/18/2025 CVE reserved
11/24/2025 +6 days Advisory disclosed
11/24/2025 +0 days VulDB entry created
11/25/2025 +1 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: github.com
Status: Not defined

CVE: CVE-2025-65498 (🔒)
GCVE (CVE): GCVE-0-2025-65498
GCVE (VulDB): GCVE-100-333380

Entryinfo

Created: 11/24/2025 16:09
Updated: 11/25/2025 14:34
Changes: 11/24/2025 16:09 (55), 11/25/2025 14:34 (2)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

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