CVE-2026-57522

Bitwarden Server < 2026.5.0 JSON Injection via Webhook Templates

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.

Affected

bitwarden · server

CVSS v4.0 VULNCHECK

2.3 LOWCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS v3.1 NVD

5.0 MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:L/A:N

CVSS v3.1 VULNCHECK

3.5 LOWCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:N/I:L/A:N

EPSS

0.46% chance of exploitation in the next 30 days, 38th percentile

Published

2026-06-25

Updated

2026-07-14

Proof-of-concept exploits (1)

• https://sanjokkarki.com.np/blog/bitwarden-webhook-json-injection

Security advisories

• https://www.vulncheck.com/advisories/bitwarden-server-json-injection-via-webhook-templates
• bitwarden/server/pull/7593

References

• CVE Record
• NVD entry