{"id":"CVE-2026-55865","aliases":["EUVD-2026-42693","GHSA-vq2f-vcc9-j8mv","PYSEC-2026-3035"],"status":"published","title":"Python Liquid: Infinite loop when parsing malformed `{% case %}` tags","description":"Python Liquid is a Python engine for the Liquid template language. Prior to 2.2.1, given a malformed {% case %} tag without an associated {% when %} or {% else %} block and no terminating {% endcase %} tag, Python Liquid hangs in an infinite loop at parse time because liquid.TokenStream.eof did not give the EOF token matching kind and value fields, allowing malicious template authors to craft templates for a denial of service attack. This issue is fixed in version 2.2.1.","severity":{"version":"4.0","score":7.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-09","score":0.00451,"percentile":0.39439,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-835"],"published":"2026-06-19T20:46:34Z","modified":"2026-10-28T02:30:52Z","fixes":[{"ecosystem":"PyPI","package":"python-liquid","fixed_in":["2.2.1"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"PyPI","package":"python-liquid","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.2.1"}]}]},{"source":"osv","ecosystem":"PyPI","package":"python-liquid","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.2.1"}]}],"versions":["0.10.0","0.10.1","0.11.0","0.5.1","0.5.2","0.5.3","0.5.5","0.5.6","0.6.0","0.6.1","0.6.2","0.6.3","0.6.4","0.7.0","0.7.1","0.7.2","0.7.3","0.7.4","0.7.5","0.7.6","0.7.7","0.8.0","0.8.1","0.9.0","1.0.0","1.0.1","1.0.2","1.0.3","1.1.0","1.1.1","1.1.2","1.1.3","1.1.4","1.1.5","1.1.6","1.1.7","1.10.0","1.10.2","1.11.0","1.12.0","1.12.1","1.12.2","1.13.0","1.2.0","1.2.1","1.3.0","1.4.0","1.4.1","1.4.2","1.4.3","1.4.4","1.4.5","1.4.6","1.4.7","1.5.0","1.5.1","1.6.0","1.6.1","1.7.0","1.8.0","1.8.1","1.9.0","1.9.1","1.9.2","1.9.3","1.9.4","2.0.0","2.0.1","2.0.2","2.1.0","2.2.0"]},{"source":"osv","ecosystem":"PyPI","package":"python-liquid","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.2.1"}]}],"versions":["0.10.0","0.10.1","0.11.0","0.5.1","0.5.2","0.5.3","0.5.5","0.5.6","0.6.0","0.6.1","0.6.2","0.6.3","0.6.4","0.7.0","0.7.1","0.7.2","0.7.3","0.7.4","0.7.5","0.7.6","0.7.7","0.8.0","0.8.1","0.9.0","1.0.0","1.0.1","1.0.2","1.0.3","1.1.0","1.1.1","1.1.2","1.1.3","1.1.4","1.1.5","1.1.6","1.1.7","1.10.0","1.10.2","1.11.0","1.12.0","1.12.1","1.12.2","1.13.0","1.2.0","1.2.1","1.3.0","1.4.0","1.4.1","1.4.2","1.4.3","1.4.4","1.4.5","1.4.6","1.4.7","1.5.0","1.5.1","1.6.0","1.6.1","1.7.0","1.8.0","1.8.1","1.9.0","1.9.1","1.9.2","1.9.3","1.9.4","2.0.0","2.0.1","2.0.2","2.1.0","2.2.0"]}],"products":[{"vendor":"jg-rp","product":"liquid"}],"references":[{"url":"https://github.com/jg-rp/liquid/security/advisories/GHSA-vq2f-vcc9-j8mv","tags":["x_refsource_CONFIRM","advisory","web"]},{"url":"https://github.com/jg-rp/liquid/commit/26db8931cf35e8433c1ca506fc32c3bb62f743d4","tags":["x_refsource_MISC","fix"]},{"url":"https://github.com/jg-rp/liquid/releases/tag/v2.2.1","tags":["x_refsource_MISC","web"]},{"url":"https://github.com/advisories/GHSA-vq2f-vcc9-j8mv","tags":["advisory"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55865.json","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-55865","tags":["advisory"]},{"url":"https://github.com/jg-rp/liquid","tags":["package"]},{"url":"https://pypi.org/project/python-liquid","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-55865","title":"Python Liquid: Infinite loop when parsing malformed `{% case %}` tags","description":"Python Liquid is a Python engine for the Liquid template language. Prior to 2.2.1, given a malformed {% case %} tag without an associated {% when %} or {% else %} block and no terminating {% endcase %} tag, Python Liquid hangs in an infinite loop at parse time because liquid.TokenStream.eof did not give the EOF token matching kind and value fields, allowing malicious template authors to craft templates for a denial of service attack. This issue is fixed in version 2.2.1.","status":"published","published":"2026-07-09T20:34:38.618Z","modified":"2026-07-14T01:16:10.895Z","cvss":[{"version":"4.0","score":7.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","level":"high","assessor":"cna"}],"cwes":["CWE-835"],"updated_at":"2026-11-02T14:20:12.260247Z"}],"euvd":[{"id":"EUVD-2026-42693","description":"Python Liquid is a Python engine for the Liquid template language. Prior to 2.2.1, given a malformed {% case %} tag without an associated {% when %} or {% else %} block and no terminating {% endcase %} tag, Python Liquid hangs in an infinite loop at parse time because liquid.TokenStream.eof did not give the EOF token matching kind and value fields, allowing malicious template authors to craft templates for a denial of service attack. This issue is fixed in version 2.2.1.","status":"published","published":"2026-07-09T20:34:38Z","modified":"2026-07-14T01:16:10Z","cvss":[{"version":"4.0","score":7.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","level":"high"}],"updated_at":"2026-11-02T18:20:00.696533Z"}],"ghsa":[{"id":"GHSA-vq2f-vcc9-j8mv","title":"Python Liquid: Infinite loop when parsing malformed `{% case %}` tags","description":"### Impact\nGiven 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.\n\n### Patches\nThe issue is fixed in version 2.2.1 with the correction of the `liquid.TokenStream.eof` attribute. The `kind` and `value` of the special EOF token are now the same, so either can be tested against `liquid.token.TOKEN_EOF`.\n\n### Workarounds\nManually correct the definition of `liquid.TokenStream.eof` before parsing any templates.\n\n```python\nimport liquid\nfrom liquid.token import TOKEN_EOF\n\nliquid.stream.TokenStream.eof = liquid.Token(TOKEN_EOF, TOKEN_EOF, -1, \"\")\n\n# ...\n```","status":"published","published":"2026-06-19T20:46:34Z","modified":"2026-06-19T20:46:35Z","cvss":[{"version":"4.0","score":5.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N","level":"medium"}],"cwes":["CWE-835"],"updated_at":"2026-11-02T14:40:31.656952Z"}],"nvd":[{"id":"CVE-2026-55865","description":"Python Liquid is a Python engine for the Liquid template language. Prior to 2.2.1, given a malformed {% case %} tag without an associated {% when %} or {% else %} block and no terminating {% endcase %} tag, Python Liquid hangs in an infinite loop at parse time because liquid.TokenStream.eof did not give the EOF token matching kind and value fields, allowing malicious template authors to craft templates for a denial of service attack. This issue is fixed in version 2.2.1.","status":"published","published":"2026-07-09T21:16:56.277Z","modified":"2026-10-25T17:10:00.197Z","cvss":[{"version":"4.0","score":7.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/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","level":"high","assessor":"secondary"}],"cwes":["CWE-835"],"updated_at":"2026-11-02T14:12:28.4135Z"}],"osv":[{"id":"CVE-2026-55865","title":"Python Liquid: Infinite loop when parsing malformed `{% case %}` tags","description":"Python Liquid is a Python engine for the Liquid template language. Prior to 2.2.1, given a malformed {% case %} tag without an associated {% when %} or {% else %} block and no terminating {% endcase %} tag, Python Liquid hangs in an infinite loop at parse time because liquid.TokenStream.eof did not give the EOF token matching kind and value fields, allowing malicious template authors to craft templates for a denial of service attack. This issue is fixed in version 2.2.1.","status":"published","published":"2026-07-09T20:34:38.618Z","modified":"2026-10-28T02:30:52.947497285Z","cvss":[{"version":"4.0","score":7.1,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","level":"high"}],"cwes":["CWE-835"],"updated_at":"2026-11-02T15:45:11.609219Z"},{"id":"GHSA-vq2f-vcc9-j8mv","title":"Python Liquid: Infinite loop when parsing malformed `{% case %}` tags","description":"### Impact\nGiven 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.\n\n### Patches\nThe issue is fixed in version 2.2.1 with the correction of the `liquid.TokenStream.eof` attribute. The `kind` and `value` of the special EOF token are now the same, so either can be tested against `liquid.token.TOKEN_EOF`.\n\n### Workarounds\nManually correct the definition of `liquid.TokenStream.eof` before parsing any templates.\n\n```python\nimport liquid\nfrom liquid.token import TOKEN_EOF\n\nliquid.stream.TokenStream.eof = liquid.Token(TOKEN_EOF, TOKEN_EOF, -1, \"\")\n\n# ...\n```","status":"published","published":"2026-06-19T20:46:34Z","modified":"2026-09-10T03:51:09.596917909Z","cvss":[{"version":"4.0","score":5.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N","level":"medium"}],"cwes":["CWE-835"],"updated_at":"2026-11-02T15:46:57.694388Z"},{"id":"PYSEC-2026-3035","title":"Python Liquid: Infinite loop when parsing malformed `{% case %}` tags","description":"### Impact\nGiven 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.\n\n### Patches\nThe issue is fixed in version 2.2.1 with the correction of the `liquid.TokenStream.eof` attribute. The `kind` and `value` of the special EOF token are now the same, so either can be tested against `liquid.token.TOKEN_EOF`.\n\n### Workarounds\nManually correct the definition of `liquid.TokenStream.eof` before parsing any templates.\n\n```python\nimport liquid\nfrom liquid.token import TOKEN_EOF\n\nliquid.stream.TokenStream.eof = liquid.Token(TOKEN_EOF, TOKEN_EOF, -1, \"\")\n\n# ...\n```","status":"published","published":"2026-07-13T15:46:21.968216Z","modified":"2026-07-13T16:33:29.033510918Z","cvss":[{"version":"4.0","score":5.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N","level":"medium"}],"updated_at":"2026-11-02T15:52:56.429374Z"}]}}