Checkmate is an open-source, self-hosted tool designed to track and monitor server hardware, uptime, response times, and incidents in real-time with beautiful visualizations. Prior to 3.9.1, the public POST /api/v1/auth/register route in server/src/api/routes/authRoutes.ts passes multipart profileImage uploads through in-memory Multer parsing before registration validation, without file-size, file-count, or MIME-type limits in server/src/api/middleware/upload.ts. An unauthenticated attacker can submit concurrent oversized files that are buffered before invalid registration or invite-token checks reject the request, exhausting memory and crashing or destabilizing the backend. This issue is fixed in version 3.9.1.
{
"cna_assigner": "GitHub_M",
"cwe_ids": [
"CWE-400",
"CWE-770"
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55241.json"
}{
"extracted_events": [
{
"range": [
{
"introduced": "0"
},
{
"fixed": "3.9.1"
}
],
"source": "AFFECTED_FIELD",
"strategy": "StringRangeExpression"
},
{
"range": [
{
"fixed": "091c36cbf338b673110b0806d76df26d52516468"
}
],
"source": "REFERENCES_COMMIT"
},
{
"original_tag": "v3.9.1",
"range": [
{
"fixed": "825bcc5fdbd0dbde9e78033ce844ab880a46083a"
}
],
"source": "REFERENCES_TAG"
}
]
}