CVE-2026-123125 · Package
NO FIX YET · SEE WHAT TO DO
The Symfony Validator's Ip constraint, in its filtered modes, fails to classify shared-space and embedded IPv4 addresses (such as ::ffff:127.0.0.1) as internal, so they pass as public. An attacker who supplies a URL or address that the application then requests can reach internal hosts, a server-side request forgery.
first public Nov 4, 2026 · 1 source
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Applications that use the Symfony Ip constraint in filtered modes to decide whether a user-supplied address is internal before the server requests it are exposed. Applications that do not use the Ip constraint for this purpose, or that do not make server-side requests to user-supplied addresses, are not affected by the SSRF path.
Not affected if no-ip-constraint, no-user-supplied-urls, static-export
Who cares php, ssrf, symfony, web-apps
composer show symfony/validator and compare the version to the fixed releases.new Ip( or #[Assert\Ip( used with filtered modes such as Ip::PRIVATE_NETWORK, Ip::PUBLIC_ONLY or Ip::ALL_NO_RES, and check whether it guards outbound requests.5.4.56The Symfony Validator component IpValidator incompletely classifies internal addresses in the filtered modes of the Ip constraint, so some internal addresses are accepted as public, which can lead to Server-Side Request Forgery (SSRF) in Symfony versions prior to 5.4.56, 6.x prior to 6.4.50, 7.x prior to 7.4.23, and 8.x prior to 8.1.11.
In these modes, IpValidator relies on the PHP flags FILTER_FLAG_NO_PRIV_RANGE and FILTER_FLAG_NO_RES_RANGE to classify addresses as public, private, or reserved. These flags do not cover shared address space (100.64.0.0/10) or IPv4-mapped, IPv4-compatible, and 6to4 IPv6 addresses, which can embed internal IPv4 addresses. A value such as ::ffff:127.0.0.1 can therefore pass validation even though it points to an internal host. Applications that rely on the Ip constraint to reject internal addresses, for example before making a server-side request to a user-supplied address, can be exposed to SSRF.
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6.4.507.4.238.1.11This page as .md · .json · CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
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