Parse Server before 8.6.115 and 9.0.0 before 9.10.7-alpha.1 validates user email address format with a regular expression whose run time grows quadratically with input length and that is applied without a length limit. An unauthenticated attacker who knows the application ID can send a sign-up request, or a logged-in user can update their own email, with a long crafted email address to block the Node.js event loop and deny service to all clients.
{
"cna_assigner": "VulnCheck",
"cwe_ids": [
"CWE-1333"
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/123xxx/CVE-2026-123487.json"
}{
"extracted_events": [
{
"range": [
{
"introduced": "9.0.0"
},
{
"fixed": "9.10.7-alpha.1"
}
],
"source": "AFFECTED_FIELD",
"strategy": "StandardRange"
},
{
"range": [
{
"introduced": "0"
},
{
"fixed": "8.6.115"
}
],
"source": "AFFECTED_FIELD",
"strategy": "StandardRange"
}
]
}