Bitwarden Server before 2026.5.0 contains a JSON injection vulnerability in IntegrationTemplateProcessor.ReplaceTokens(), which substitutes user-controlled values into event-integration templates without JSON encoding. When an organization has configured an event integration whose template references a user-controlled token (such as #ActingUserName# or #UserName#, populated from a member's display name), an authenticated member can set their display name to JSON metacharacters and inject arbitrary key-value pairs into the rendered payloads delivered to webhook, SIEM, Slack, Teams, or Datadog endpoints, making injected fields indistinguishable from legitimate template output.
{
"cna_assigner": "VulnCheck",
"cwe_ids": [
"CWE-74"
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/57xxx/CVE-2026-57522.json"
}{
"source": [
"CPE_RANGE",
"REFERENCES"
],
"cpe": "cpe:2.3:a:bitwarden:server:*:*:*:*:*:*:*:*",
"extracted_events": [
{
"introduced": "0"
},
{
"fixed": "2026.5.0"
}
]
}