CVE-2026-55865: Python Liquid: Infinite loop when parsing malformed `{% case %}` tags

June 19, 2026

Given a malformed {% case %} tag without associated {% when %} or {% else %} block, and no terminating {% endcase %} tag, Python Liquid hangs in an infinite loop at parse time. This allows malicious template authors to craft templates for a denial of service attack.

References

github.com/advisories/GHSA-vq2f-vcc9-j8mv
github.com/jg-rp/liquid/security/advisories/GHSA-vq2f-vcc9-j8mv
nvd.nist.gov/vuln/detail/CVE-2026-55865

Code Behaviors & Features

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