CVE-2026-109413: symfony 0 to before v5.4.54, v6.0.0-BETA1 to before v6.4.45, v7.0.0-BETA1 to before v7.4.18, v8.0.0-BETA1 to before…

Affected technology

symfony · 0 to before v5.4.54, v6.0.0-BETA1 to before v6.4.45, v7.0.0-BETA1 to before v7.4.18, v8.0.0-BETA1 to before v8.1.6
sensiolabs

Description’s affected range: prior to versions 5.4.54

Component: Symfony\\Component\\Yaml\\Parser::lexInlineStructure()

Attack conditions (Source advisory, CVSS 4.0): Network (remote) · No privileges required · No user interaction required

What an attacker can do

Source advisory’s CVSS 4.0 assessment (base score 8.7/10) rates confidentiality and integrity impact as none; availability impact as high. The description does not specify what an attacker can achieve beyond these rated impacts.