CVE-2026-21888: high-severity vulnerability in nanomq
MQTT v5 Variable Byte Integer parsing out-of-bounds: get_var_integer()
Published
E-mail alert when it lands in KEV, gets a public PoC or its score goes up.
21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 7.5epss 0.4%
NanoMQ MQTT Broker (NanoMQ) is an all-around Edge Messaging Platform. MQTT v5 Variable Byte Integer parsing out-of-bounds: get_var_integer() accepts 5-byte varints without bounds checks; reliably triggers OOB read / crash when built with ASan. This affects 0.24.6 and earlier.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Affected products
nanomq · nanomqRelated CVEs — nanomq
In the same product, most dangerous first.
CVE-2026-32135HIGHNanoMQ has Heap Buffer Overflow in URI Parameter ParsingEPSS 0.5%CVE-2026-25627MEDIUMnanomq: OOB Read / Crash (DoS) via Malformed MQTT Remaining Length over WebSocketEPSS 0.5%CVE-2026-44639LOWNanoMQ: O(N²) Denial of Service in MQTT v5 Property ParsingEPSS 0.4%CVE-2026-32696LOWNanoMQ HTTP Auth: Missing username/password can trigger a NULL-pointer strlen() in auth_http.c:set_data(), causing a process crash — SIGSEGV, remotely triggerableEPSS 0.4%CVE-2026-47276MEDIUMNULL Pointer Dereference in REST API properties_parse via Malformed user_propertiesEPSS 0.4%CVE-2026-32134MEDIUMNanoMQ: NULL Pointer Dereference Crash in tcptran_pipe_peer During Session RestoreEPSS 0.4%