CVE-2026-48784: Symfony: UrlGenerator Dot-Segment Encoding Skips Every Other Chained `../` or `./` → Generated URL Collapses Off-Route Under RFC 3986 Normalization

Description

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.

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Attack vector

Network

Complexity

Low

Privileges

None

User interaction

Required

Confidentiality

Low

Integrity

Low

Availability

None

Scope

Changed

Exploitation

Is it being used?

Exploit prediction (EPSS)0.3% · higher than 28% of CVEs

Exploited in the wildNo evidence yet

CISA KEVNot listed

Ransomware campaign useNot known

Affected products

Which versions

RO

routing · 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 · source: vendor

SY

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 · source: vendor, NVD