Junglewise Threat Intelligence

CVE-2026-48784: Symfony Routing improper dot-segment encoding in UrlGenerator

CVE-2026-48784 · Severity: medium · CVSS 6.9 · Published 2026-07-14

Vendors: Symfony.

Executive brief

Symfony is a popular PHP framework used to build web applications. A flaw in its URL generation component could allow an attacker to manipulate web addresses, potentially leading to users being redirected to unintended or malicious pages. This occurs because the system fails to properly encode certain path sequences, causing the final URL to point to a different location than intended when processed by web browsers or proxies.

Technical details

A vulnerability exists in Symfony's UrlGenerator::doGenerate() method due to an improper implementation of dot-segment encoding. The component used strtr() to percent-encode '.' and '..' segments to prevent path traversal during RFC 3986 normalization; however, because strtr() advances past the trailing slash of a match, it skipped every other segment in a chained sequence (e.g., '/../../'). If a route uses permissive requirements (like .+ or .*) for parameters, an attacker can provide chained dot-segments that result in a generated URL collapsing to a different path than the intended route. This can lead to open redirects or path confusion when processed by strict RFC 3986 consumers like reverse proxies or browsers. The issue is fixed in versions 5.4.53, 6.4.41, 7.4.13, and 8.0.13.

Affected products

  • Symfony symfony/symfony < 5.4.53, >= 6.0.0-BETA1 < 6.4.41, >= 7.0.0-BETA1 < 7.4.13, >= 8.0.0-BETA1 < 8.0.13
  • Symfony symfony/routing < 5.4.53, >= 6.0.0-BETA1 < 6.4.41, >= 7.0.0-BETA1 < 7.4.13, >= 8.0.0-BETA1 < 8.0.13

Timeline

  • 2026-05-27: patched: Fixes released in multiple branches
  • 2026-05-27: advisory: GitHub Security Advisory GHSA-h5x3-xfc9-m39h published
  • 2026-07-14: disclosed: CVE-2026-48784 published to NVD

References

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