High
MQTT v5 Variable Byte Integer parsing out-of-bounds: get_var_integer()
Type: advisorySources: OSV
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.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2026-21888
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 3 Nov 2026, 16:06 UTC · Revision 1
Source evidence
MQTT v5 Variable Byte Integer parsing out-of-bounds: get_var_integer()
core-osv · Original sourcePublished 11 Mar 2026, 15:22 UTC
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.
osv:CVE-2026-21888
Complete source record
{
"id": "b7074ee8fadffb98b3e97ad1d5febf94cbca6b75c14905d83b2fc46c5a3cbe52",
"url": "https://osv.dev/vulnerability/CVE-2026-21888",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "MQTT v5 Variable Byte Integer parsing out-of-bounds: get_var_integer()",
"summary": "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.",
"evidence": "osv:CVE-2026-21888",
"products": [],
"severity": "high",
"structured": {
"id": "CVE-2026-21888",
"aliases": [
"CVE-2026-21888",
"GHSA-cggc-6m7w-j7x5"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://github.com/nanomq/nanomq",
"type": "GIT",
"events": [
{
"introduced": "0"
},
{
"last_affected": "dc3a3136cd82d5c005b8cd26a65fe53beaaf0eb9"
}
],
"database_specific": {
"extracted_events": [
{
"range": [
{
"introduced": "0"
},
{
"last_affected": "0.24.6"
}
],
"source": "AFFECTED_FIELD",
"strategy": "StringRangeExpression"
},
{
"cpe": "cpe:2.3:a:emqx:nanomq:*:*:*:*:*:*:*:*",
"range": [
{
"introduced": "0"
},
{
"last_affected": "0.24.6"
}
],
"source": "CPE_RANGE"
}
]
}
}
],
"versions": [
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],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-21888.json"
}
}
],
"modified": "2026-10-28T02:30:30.376071951Z",
"provider": "osv",
"references": [
"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/21xxx/CVE-2026-21888.json",
"https://github.com/nanomq/nanomq/security/advisories/GHSA-cggc-6m7w-j7x5",
"https://nvd.nist.gov/vuln/detail/CVE-2026-21888",
"https://github.com/nanomq/nanomq/issues/2192"
],
"provider_metadata": {
"cwe_ids": [
"CWE-125"
],
"cna_assigner": "GitHub_M",
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/21xxx/CVE-2026-21888.json"
}
},
"related_cves": [
{
"value": "CVE-2026-21888",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 497132,
"published_at": "2026-03-11T15:22:32.463+00:00"
}