What’s Vulnerable › Vulnerabilities

CVE-2026-48736: Symfony: IpUtils::PRIVATE_SUBNETS Omits IPv6 Transition Forms (6to4, NAT64, Teredo, IPv4-compatible): SSRF Bypass in NoPrivateNetworkHttpClient

• Severity: high (CVSS 8.6 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-07-14 · updated 2026-07-16
• Weakness: CWE-184

Description

Symfony is a PHP framework for web and console applications and a set of reusable PHP components. From 5.4.0 to 5.4.53, 6.4.41, 7.4.13, and 8.0.13, NoPrivateNetworkHttpClient and IpUtils::PRIVATE_SUBNETS omitted IPv6 transition prefixes such as 6to4, NAT64, Teredo, and IPv4-compatible IPv6, allowing attacker-supplied URLs to represent private IPv4 targets in forms that IpUtils::isPrivateIp() did not block. This issue is fixed in versions 5.4.53, 6.4.41, 7.4.13, and 8.0.13.

Affected products

• symfony: from 5.4.0 before 5.4.43; from 6.4.0 before 6.4.41; from 7.0.0 before 7.4.13; from 8.0.0 before 8.0.13 — fixed in 5.4.43, 6.4.41, 7.4.13, 8.0.13

How to fix

Upgrade to a fixed version: symfony 5.4.43, 6.4.41, 7.4.13, 8.0.13. Check the vendor advisory for mitigations.

References

• https://github.com/symfony/symfony/commit/82765368cf74177c36613575182f168a2eb765b2
• https://github.com/symfony/symfony/commit/85b831555be8ea1f43bf01078afe87bc4c92f65e
• https://github.com/symfony/symfony/releases/tag/v5.4.53
• https://github.com/symfony/symfony/releases/tag/v6.4.41
• https://github.com/symfony/symfony/releases/tag/v7.4.13
• https://github.com/symfony/symfony/security/advisories/GHSA-38cx-cq6f-5755

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