Twig: The `spaceless` filter implicitly marks its output as safe
The advisory, in context
Description
The spaceless filter is registered with is_safe => ['html'], which means Twig's autoescaper does not escape its output in an HTML context. As a result, applying spaceless to attacker-controlled input that contains markup emits the markup unescaped even when the developer never wrote |raw and autoescape is enabled.
Example:
{% set payload = '<script>alert()</script>' %}
{{ payload }} {# escaped #}
{{ payload|spaceless }} {# not escaped #}
The filter is deprecated but still functional. With the deprecation, some downstream projects (e.g. Drupal modules) have duplicated the filter and inherited the same is_safe flag.
Resolution
The spaceless filter no longer marks its output as safe. Documentation has been updated to warn that spaceless should not be applied to unsanitised user input.
Credits
Twig would like to thank Pierre Rudloff for reporting the issue.
Affected packages
Start with the recorded fix for your release branch. Check your installed version and test compatibility before upgrading. Fixing this advisory does not rule out other vulnerabilities in the release.
Earlier releases before 3.26.0
Fixed in 3.26.0
242 explicitly affected versions
1.3.0, 1.4.0, 1.5.0, 1.5.1, 1.6.0, 1.6.1, 1.6.2, 1.6.3, 1.6.4, 1.6.5, v1.10.0, v1.10.1, v1.10.2, v1.10.3, v1.11.0, v1.11.1, v1.12.0, v1.12.0-RC1, v1.12.1, v1.12.2, v1.12.3, v1.13.0, v1.13.1, v1.13.2, v1.14.0, v1.14.1, v1.14.2, v1.15.0, v1.15.1, v1.16.0, v1.16.1, v1.16.2, v1.16.3, v1.17.0, v1.18.0, v1.18.1, v1.18.2, v1.19.0, v1.20.0, v1.21.0, v1.21.1, v1.21.2, v1.22.0, v1.22.1, v1.22.2, v1.22.3, v1.23.0, v1.23.1, v1.23.2, v1.23.3, v1.24.0, v1.24.1, v1.24.2, v1.25.0, v1.26.0, v1.26.1, v1.27.0, v1.28.0, v1.28.1, v1.28.2, v1.29.0, v1.30.0, v1.31.0, v1.32.0, v1.33.0, v1.33.1, v1.33.2, v1.34.0, v1.34.1, v1.34.2, v1.34.3, v1.34.4, v1.35.0, v1.35.1, v1.35.2, v1.35.3, v1.35.4, v1.36.0, v1.37.0, v1.37.1, v1.38.0, v1.38.1, v1.38.2, v1.38.3, v1.38.4, v1.39.0, v1.39.1, v1.40.0, v1.40.1, v1.41.0, v1.42.0, v1.42.1, v1.42.2, v1.42.3, v1.42.4, v1.42.5, v1.43.0, v1.43.1, v1.44.0, v1.44.1, v1.44.2, v1.44.3, v1.44.4, v1.44.5, v1.44.6, v1.44.7, v1.44.8, v1.7.0, v1.8.0, v1.8.1, v1.8.2, v1.8.3, v1.9.0, v1.9.1, v1.9.2, v2.0.0, v2.1.0, v2.10.0, v2.11.0, v2.11.1, v2.11.2, v2.11.3, v2.12.0, v2.12.1, v2.12.2, v2.12.3, v2.12.4, v2.12.5, v2.13.0, v2.13.1, v2.14.0, v2.14.1, v2.14.10, v2.14.11, v2.14.12, v2.14.13, v2.14.2, v2.14.3, v2.14.4, v2.14.5, v2.14.6, v2.14.7, v2.14.8, v2.14.9, v2.15.0, v2.15.1, v2.15.2, v2.15.3, v2.15.4, v2.15.5, v2.15.6, v2.16.0, v2.16.1, v2.2.0, v2.3.0, v2.3.1, v2.3.2, v2.4.0, v2.4.1, v2.4.2, v2.4.3, v2.4.4, v2.4.5, v2.4.6, v2.4.7, v2.4.8, v2.5.0, v2.6.0, v2.6.1, v2.6.2, v2.7.0, v2.7.1, v2.7.2, v2.7.3, v2.7.4, v2.8.0, v2.8.1, v2.9.0, v3.0.0, v3.0.0-BETA1, v3.0.1, v3.0.2, v3.0.3, v3.0.4, v3.0.5, v3.1.0, v3.1.1, v3.10.0, v3.10.1, v3.10.2, v3.10.3, v3.11.0, v3.11.1, v3.11.2, v3.11.3, v3.12.0, v3.13.0, v3.14.0, v3.14.1, v3.14.2, v3.15.0, v3.16.0, v3.17.0, v3.17.1, v3.18.0, v3.19.0, v3.2.1, v3.20.0, v3.21.0, v3.21.1, v3.22.0, v3.22.1, v3.22.2, v3.23.0, v3.24.0, v3.25.0, v3.3.0, v3.3.1, v3.3.10, v3.3.2, v3.3.3, v3.3.4, v3.3.5, v3.3.6, v3.3.7, v3.3.8, v3.3.9, v3.4.0, v3.4.1, v3.4.2, v3.4.3, v3.5.0, v3.5.1, v3.6.0, v3.6.1, v3.7.0, v3.7.1, v3.8.0, v3.9.0, v3.9.1, v3.9.2, v3.9.3
View affected-version evidence
{
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "3.26.0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"1.3.0",
"1.4.0",
"1.5.0",
"1.5.1",
"1.6.0",
"1.6.1",
"1.6.2",
"1.6.3",
"1.6.4",
"1.6.5",
"v1.10.0",
"v1.10.1",
"v1.10.2",
"v1.10.3",
"v1.11.0",
"v1.11.1",
"v1.12.0",
"v1.12.0-RC1",
"v1.12.1",
"v1.12.2",
"v1.12.3",
"v1.13.0",
"v1.13.1",
"v1.13.2",
"v1.14.0",
"v1.14.1",
"v1.14.2",
"v1.15.0",
"v1.15.1",
"v1.16.0",
"v1.16.1",
"v1.16.2",
"v1.16.3",
"v1.17.0",
"v1.18.0",
"v1.18.1",
"v1.18.2",
"v1.19.0",
"v1.20.0",
"v1.21.0",
"v1.21.1",
"v1.21.2",
"v1.22.0",
"v1.22.1",
"v1.22.2",
"v1.22.3",
"v1.23.0",
"v1.23.1",
"v1.23.2",
"v1.23.3",
"v1.24.0",
"v1.24.1",
"v1.24.2",
"v1.25.0",
"v1.26.0",
"v1.26.1",
"v1.27.0",
"v1.28.0",
"v1.28.1",
"v1.28.2",
"v1.29.0",
"v1.30.0",
"v1.31.0",
"v1.32.0",
"v1.33.0",
"v1.33.1",
"v1.33.2",
"v1.34.0",
"v1.34.1",
"v1.34.2",
"v1.34.3",
"v1.34.4",
"v1.35.0",
"v1.35.1",
"v1.35.2",
"v1.35.3",
"v1.35.4",
"v1.36.0",
"v1.37.0",
"v1.37.1",
"v1.38.0",
"v1.38.1",
"v1.38.2",
"v1.38.3",
"v1.38.4",
"v1.39.0",
"v1.39.1",
"v1.40.0",
"v1.40.1",
"v1.41.0",
"v1.42.0",
"v1.42.1",
"v1.42.2",
"v1.42.3",
"v1.42.4",
"v1.42.5",
"v1.43.0",
"v1.43.1",
"v1.44.0",
"v1.44.1",
"v1.44.2",
"v1.44.3",
"v1.44.4",
"v1.44.5",
"v1.44.6",
"v1.44.7",
"v1.44.8",
"v1.7.0",
"v1.8.0",
"v1.8.1",
"v1.8.2",
"v1.8.3",
"v1.9.0",
"v1.9.1",
"v1.9.2",
"v2.0.0",
"v2.1.0",
"v2.10.0",
"v2.11.0",
"v2.11.1",
"v2.11.2",
"v2.11.3",
"v2.12.0",
"v2.12.1",
"v2.12.2",
"v2.12.3",
"v2.12.4",
"v2.12.5",
"v2.13.0",
"v2.13.1",
"v2.14.0",
"v2.14.1",
"v2.14.10",
"v2.14.11",
"v2.14.12",
"v2.14.13",
"v2.14.2",
"v2.14.3",
"v2.14.4",
"v2.14.5",
"v2.14.6",
"v2.14.7",
"v2.14.8",
"v2.14.9",
"v2.15.0",
"v2.15.1",
"v2.15.2",
"v2.15.3",
"v2.15.4",
"v2.15.5",
"v2.15.6",
"v2.16.0",
"v2.16.1",
"v2.2.0",
"v2.3.0",
"v2.3.1",
"v2.3.2",
"v2.4.0",
"v2.4.1",
"v2.4.2",
"v2.4.3",
"v2.4.4",
"v2.4.5",
"v2.4.6",
"v2.4.7",
"v2.4.8",
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"v2.6.0",
"v2.6.1",
"v2.6.2",
"v2.7.0",
"v2.7.1",
"v2.7.2",
"v2.7.3",
"v2.7.4",
"v2.8.0",
"v2.8.1",
"v2.9.0",
"v3.0.0",
"v3.0.0-BETA1",
"v3.0.1",
"v3.0.2",
"v3.0.3",
"v3.0.4",
"v3.0.5",
"v3.1.0",
"v3.1.1",
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"v3.11.1",
"v3.11.2",
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"v3.14.0",
"v3.14.1",
"v3.14.2",
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"v3.16.0",
"v3.17.0",
"v3.17.1",
"v3.18.0",
"v3.19.0",
"v3.2.1",
"v3.20.0",
"v3.21.0",
"v3.21.1",
"v3.22.0",
"v3.22.1",
"v3.22.2",
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]
}