Symfony: UrlGenerator Dot-Segment Encoding Skips Every Other Chained `../` or `./` → Generated URL Collapses Off-Route Under RFC 3986 Normalization

Summary

Symfony is a PHP framework for web and console applications and a set of reusable PHP components. Prior to 5.4.53, 6.4.41, 7.4.13, and 8.0.13, UrlGenerator::doGenerate() used strtr() dot-segment encoding that skipped every other chained ../ or ./ segment, allowing attacker-controlled route parameters to generate URLs that collapse to a different path under RFC 3986 normalization. This issue is fixed in versions 5.4.53, 6.4.41, 7.4.13, and 8.0.13.

Timeline

1. Jul 14, 2026, 7:04 PM UTCCVE published
2. Jul 15, 2026, 1:23 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: yes · Technical impact: partial

3. Jul 15, 2026, 1:27 PM UTCRecord last updated

Affected versions

• symfony symfony

  fixed in 5.4.53; From 6.0.0-BETA1 · fixed in 6.4.41; From 7.0.0-BETA1 · fixed in 7.4.13; From 8.0.0-BETA1 · fixed in 8.0.13

• symfony routing

  fixed in 5.4.53; From 6.0.0-BETA1 · fixed in 6.4.41; From 7.0.0-BETA1 · fixed in 7.4.13; From 8.0.0-BETA1 · fixed in 8.0.13

• symfony/routingPackagist

  fixed in 5.4.53

• symfony/routingPackagist

  From 6.0.0 · fixed in 6.4.41

• symfony/routingPackagist

  From 7.0.0 · fixed in 7.4.13

• symfony/routingPackagist

  From 8.0.0 · fixed in 8.0.13

• symfony/symfonyPackagist

  fixed in 5.4.53

• symfony/symfonyPackagist

  From 6.0.0 · fixed in 6.4.41

• symfony/symfonyPackagist

  From 7.0.0 · fixed in 7.4.13

• symfony/symfonyPackagist

  From 8.0.0 · fixed in 8.0.13

References 5