CVE-2026-26456
HighCVSS 7.5Exploitation Probability (EPSS)
Low risk18th percentile - higher than 18% of all known CVEs
Summary
In ccoap (commit 77f55c4b466e99327c24ace8a2913d3ba7e2ccd5), a null pointer dereference vulnerability exists in the server-side session management logic. The issue is caused by a race condition between the request dispatch thread and the session cleanup thread when accessing shared session list nodes without proper synchronization.
Risk Assessment
An attacker can exploit the race condition to cause a server crash (DoS) or potentially gain unauthorized access to sessions.
Recommendation
Update ccoap to a version with synchronization fixes or restrict access to the COAP server.
Other vulnerabilities in ccoap
See all- CVE-2026-26459High
ccoap (commit 77f55c4b466e99327c24ace8a2913d3ba7e2ccd5) contains a vulnerability in the option parsing logic that causes a segmentation fault when processing malformed COAP messages with insufficient option data.
- CVE-2026-26457High
ccoap (commit 77f55c4b466e99327c24ace8a2913d3ba7e2ccd5) contains a null pointer dereference vulnerability in the coap_dump_msg() function when processing COAP messages containing options with zero length.
- CVE-2026-26453High
ccoap (commit 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.
- CVE-2026-26452High
ccoap (commit 77f55c4b466e99327c24ace8a2913d3ba7e2ccd5) contains a vulnerability in the option parsing logic that causes a segmentation fault when processing COAP messages containing invalid option numbers.
Original NVD description (English source)
A null pointer dereference vulnerability exists in the server-side session management logic of ccoap 77f55c4b466e99327c24ace8a2913d3ba7e2ccd5. The issue is caused by a race condition between the request dispatch thread and the session cleanup thread when accessing shared session list nodes without proper synchronization.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS