CVE-2026-26453

Deferred Deferred - Pending Action

Null Pointer Dereference in ccoap COAP Server

Publication date: 2026-08-27

Last updated on: 2026-09-01

Assigner: MITRE

Description

ccoap 77f55c4b466e99327c24ace8a2913d3ba7e2ccd5 contains a null pointer dereference vulnerability in the coap_server_handle_session() function when processing COAP messages containing URI_PATH options with NULL data pointers. When the server searches for a URI_PATH option matching the string "separate", it directly calls strncmp() on option_list[i].data without checking if the pointer is NULL. This causes a segmentation fault when the option's data field is NULL.

CVSS Scores

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Meta Information

Published

2026-08-27

Last Modified

2026-09-01

Generated

2026-09-17

AI Q&A

2026-08-27

EPSS Evaluated

2026-09-15

NVD

CVE-2026-26453

EUVD

EUVD-2026-67096

Affected Vendors & Products

Currently, no data is known.

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-476	The product dereferences a pointer that it expects to be valid but is NULL.

Attack-Flow Graph

Executive Summary

CVE-2026-26453 is a null pointer dereference vulnerability in the ccoap library affecting the coap_server_handle_session() function. It occurs when processing COAP messages with URI_PATH options that have NULL data pointers. The code searches for URI_PATH options matching 'separate' by calling strncmp() without checking if the data pointer is NULL, causing a segmentation fault when the pointer is NULL.

Detection Guidance

To detect this vulnerability, monitor for segmentation faults in applications using the ccoap library, particularly when processing COAP messages with URI_PATH options. Check logs for crashes in coap_server_handle_session() or related functions. Use network traffic analysis tools like Wireshark to inspect COAP packets for malformed URI_PATH options with NULL data pointers.

Impact Analysis

This vulnerability can cause a denial of service by crashing the COAP server when it processes malformed messages with NULL data pointers in URI_PATH options. Attackers could exploit this to make the server unavailable.

Compliance Impact

This vulnerability causes a segmentation fault due to a null pointer dereference, which could lead to denial of service conditions in systems processing COAP messages. Such instability may violate compliance requirements for availability in standards like GDPR (Article 32) and HIPAA (Security Rule), which mandate reliable access to personal or health data.

Mitigation Strategies

Immediately update the ccoap library to a patched version that includes NULL pointer checks before calling strncmp() in coap_server_handle_session(). If an update is unavailable, apply a temporary fix by adding the NULL check manually in server.c at lines 666-674. Validate all COAP messages to ensure URI_PATH options have non-NULL data pointers before processing.

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