Twig: The spaceless filter implicitly marks its output as safe

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

1.3 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:U · score source

EPSS

• CVE-2026-46628: 0.29% estimated exploitation activity in the next 30 days; percentile 22.23 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Description The spaceless filter is registered with issafe = ['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: 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 issafe 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.

Published by the source

21 May 2026, 21:21 UTC

Last modified by the source

21 May 2026, 21:21 UTC

Source last checked

26 Oct 2026, 14:40 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-4j38-f5cw-54h7

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# Patch Next advisory brief: CVE-2026-46628

Advisory: Twig: The `spaceless` filter implicitly marks its output as safe
IDs: CVE-2026-46628, GHSA-4j38-f5cw-54h7
Record: https://patchnext.com/advisories/cve-2026-46628 (revision 1, source checked 26 Oct 2026, 14:40 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Low (CVSS 1.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: twig/twig 3.26.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist twig/twig: affected < 3.26.0; fixed in 3.26.0

## Suggested inspection (read-only)
- Packagist twig/twig: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on twig/twig.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-4j38-f5cw-54h7 (GitHub-reviewed advisory GHSA-4j38-f5cw-54h7 lists affected ranges: Packagist twig/twig >=0 <3.26.0)

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