Bitwarden Server prior to v2026.4.0 contains a missing authorization vulnerability that allows a provider service user to add an arbitrary organization to their provider via POST /providers/{providerId}/clients/existing, resulting in takeover of the target organization; self-hosted installations are unaffected as this endpoint is restricted to Cloud via SelfHosted(NotSelfHostedOnly = true).
{
"cwe_ids": [
"CWE-862"
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/43xxx/CVE-2026-43639.json",
"cna_assigner": "VulnCheck"
}{
"cpe": "cpe:2.3:a:bitwarden:server:*:*:*:*:*:*:*:*",
"extracted_events": [
{
"introduced": "0"
},
{
"fixed": "2026.4.0"
}
],
"source": [
"CPE_RANGE",
"REFERENCES"
]
}