CVE-2026-57522

low

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.

References

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

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

https://github.com/bitwarden/server/releases/tag/v2026.5.0

https://github.com/bitwarden/server/pull/7593

https://github.com/bitwarden/server/commit/a26afd18130ef985ede5c97d277820d045185a28

Details

Source: Mitre, NVD

Published: 2026-06-25

Updated: 2026-06-27

Risk Information

CVSS v2

Base Score: 4

Vector: CVSS2#AV:N/AC:L/Au:S/C:N/I:P/A:N

Severity: Medium

CVSS v3

Base Score: 5

Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:L/A:N

Severity: Medium

CVSS v4

Base Score: 2.3

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

Severity: Low

EPSS

EPSS: 0.00204