CVE-2026-33130 PUBLISHED

Uptime Kuma: SSTI in Notification Templates Allows Arbitrary File Read (Incomplete Fix for GHSA-vffh-c9pq-4crh)

Assigner: GitHub_M
Reserved: 17.03.2026 Published: 20.03.2026 Updated: 20.03.2026

Uptime Kuma is an open source, self-hosted monitoring tool. In versions 1.23.0 through 2.2.0, the fix from GHSA-vffh-c9pq-4crh doesn't fully work to preventServer-side Template Injection (SSTI). The three mitigations added to the Liquid engine (root, relativeReference, dynamicPartials) only block quoted paths. If a project uses an unquoted absolute path, attackers can still read any file on the server. The original fix in notification-provider.js only constrains the first two steps of LiquidJS's file resolution (via root, relativeReference, and dynamicPartials options), but the third step, the require.resolve() fallback in liquid.node.js has no containment check, allowing unquoted absolute paths like /etc/passwd to resolve successfully. Quoted paths happen to be blocked only because the literal quote characters cause require.resolve('"/etc/passwd"') to throw a MODULE_NOT_FOUND error, not because of any intentional security measure. This issue has been fixed in version 2.2.1.

Metrics

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
CVSS Score: 6.5

Product Status

Vendor louislam
Product uptime-kuma
Versions
  • Version >= 1.23.0, < 2.2.1 is affected

References

Problem Types

  • CWE-98: Improper Control of Filename for Include/Require Statement in PHP Program ('PHP Remote File Inclusion') CWE
  • CWE-1336: Improper Neutralization of Special Elements Used in a Template Engine CWE