Summary
Twig: The spaceless filter implicitly marks its output as safe
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.
Impact
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2026-46628? CVE-2026-46628 is a low-severity security vulnerability in twig/twig (composer), affecting versions < 3.26.0. It is fixed in 3.26.0.
- Which versions of twig/twig are affected by CVE-2026-46628? twig/twig (composer) versions < 3.26.0 is affected.
- Is there a fix for CVE-2026-46628? Yes. CVE-2026-46628 is fixed in 3.26.0. Upgrade to this version or later.
- Is CVE-2026-46628 exploitable, and should I be worried? Whether CVE-2026-46628 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-46628 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-46628? Upgrade
twig/twigto 3.26.0 or later.