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Advisories

Bitwarden Server < 2026.5.0 JSON Injection via Webhook Templates

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severity
low
date
Affecting

  • server < 2026.5.0

CWE
  • CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
CVSS
2.3
CVSS V4 Vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N
Credit
Sanjok Karki
Description
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.

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