What is CVE-2024-40493?

CVE-2024-40493 is a critical-severity vulnerability in Keith-Cullen Freecoap, classified under NULL Pointer Dereference. CVSS score: 9.8/10. Published 2024-10-22.

How severe is CVE-2024-40493?

Critical severity. CVSS v3 base score is 9.8 out of 10.

NULL pointer dereference in Keith-Cullen Freecoap

CVE-2024-40493

Null Pointer Dereference in `coap_client_exchange_blockwise2` function in Keith Cullen FreeCoAP 1.0 allows remote attackers to cause a denial of service and potentially execute arbitrary code via a specially crafted CoAP packet that causes `coap_msg_get_payload(resp)` to return a null pointer, which is then dereferenced in a call to `memcpy`.

Published 2024-10-22 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.008 (54.4th percentile), scored 2026-10-01.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 54th percentile — 54.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.008 · newest: 0.008 · change: 0.000

Affected products

Keith-Cullen Freecoap — versions 1.0

Weakness classification (CWE)

CWE-476 — NULL Pointer Dereference

References

github.com/keith-cullen/FreeCoAP/issues/37 (Exploit, Issue Tracking)
gist.github.com/dqp10515/fe80005e2fb58ed8ada178ac017e4ad4 (Third Party Advisory)

Frequently asked questions

What is CVE-2024-40493?: CVE-2024-40493 is a critical-severity vulnerability in Keith-Cullen Freecoap, classified under NULL Pointer Dereference. CVSS score: 9.8/10. Published 2024-10-22.
How severe is CVE-2024-40493?: Critical severity. CVSS v3 base score is 9.8 out of 10.