NULL pointer dereference in Emqx Nanomq
CVE-2026-32696
NanoMQ MQTT Broker (NanoMQ) is an all-around Edge Messaging Platform. In NanoMQ version 0.24.6, after enabling auth.http_auth (HTTP authentication), when a client connects to the broker using MQTT CONNECT without providing username/password, and the configuration params uses the placeholders %u / %P (e.g., username="%u", password="%P"), the HTTP request construction phase enters auth_http.c:set_data(). This results in calling strlen() on a NULL pointer, causing a SIGSEGV crash. This crash can be triggered remotely, resulting in a denial of service. This issue has been patched in version 0.24.7.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 3.1 (Low). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:L.
EPSS exploit prediction
EPSS: 0.006 (44.4th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 44th percentile — 44.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.006 · change: +0.002
Affected products
- Emqx Nanomq
- Nanomq — versions >= 0.24.6, < 0.24.7
Weakness classification (CWE)
References
- github.com/nanomq/nanomq/security/advisories/GHSA-77f4-wvq8-mp3p (Exploit, Vendor Advisory)
- github.com/nanomq/NanoNNG/pull/1394 (Patch, Issue Tracking)
- github.com/nanomq/NanoNNG/commit/c20aa27e5290bb480a5315099952480d35f37a8b (Patch)
- github.com/nanomq/nanomq/releases/tag/0.24.7 (Product, Release Notes)
Frequently asked questions
- What is CVE-2026-32696?
- CVE-2026-32696 is a low-severity vulnerability in Emqx Nanomq, classified under NULL Pointer Dereference. CVSS score: 3.1/10. Published 2026-03-30.
- How severe is CVE-2026-32696?
- Low severity. CVSS v3 base score is 3.1 out of 10.