EUVD-2026-18464Severity by source
AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
Primary rating from GitHub Advisory · only source for this CVE.
CVSS VectorGitHub Advisory
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
Lifecycle Timeline
4DescriptionGitHub Advisory
NanoMQ MQTT Broker (NanoMQ) is an all-around Edge Messaging Platform. Prior to version 0.24.10, in NanoMQ's webhook_inproc.c, the hook_work_cb() function processes nng messages by parsing the message body with cJSON_Parse(body). The body is obtained from nng_msg_body(msg), which is a binary buffer without a guaranteed null terminator. This leads to an out-of-bounds read (OOB read) as cJSON_Parse reads until it finds a \0, potentially accessing memory beyond the allocated buffer (e.g., nng_msg metadata or adjacent heap/stack). The issue is often masked by nng's allocation padding (extra 32 bytes of zeros for non-power-of-two sizes <1024 or non-aligned). The overflow is reliably triggered when the JSON payload length is a power-of-two >=1024 (no padding added). This issue has been patched in version 0.24.10.
AnalysisAI
Out-of-bounds read in NanoMQ MQTT Broker webhook processing allows remote attackers with high privileges to trigger denial of service by sending malformed JSON payloads. Prior to version 0.24.10, the hook_work_cb() function in webhook_inproc.c passes unsanitized binary message buffers directly to cJSON_Parse(), which reads past buffer boundaries when payloads lack null terminators. …
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Vulnerability AssessmentAI
| Risk Assessment | CVSS 4.9 reflects moderate severity with network accessibility and low complexity, but the requirement for PR:H (high privilege) significantly constrains real-world attack surface. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | A high-privilege NanoMQ administrator with webhook configuration access crafts a webhook message with a JSON payload exactly 1024 bytes long (or another power-of-two >=1024), intentionally omitting a null terminator. When the message is delivered to the broker's intra-process webhook handler, cJSON_Parse() reads beyond the allocated buffer boundary, accessing adjacent heap memory (possibly message metadata or other NanoMQ internal structures). … |
| Remediation | Upgrade NanoMQ to version 0.24.10 or later, which includes a patched version of webhook_inproc.c that properly null-terminates message bodies before passing them to cJSON_Parse(). … Detailed patch versions, workarounds, and compensating controls in full report. |
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