# CVE-2026-48736: Symfony: IpUtils::PRIVATE_SUBNETS Omits IPv6 Transition Forms (6to4, NAT64, Teredo, IPv4-compatible): SSRF Bypass in NoPrivateNetworkHttpClient > Attackers can bypass private network restrictions in Symfony's HTTP client using IPv6 transition forms to access internal resources. - **Severity:** Medium 6.9 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:L/SA:N`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 14 Jul 2026 - **Updated:** 15 Jul 2026 - **Also known as:** DEBIAN-CVE-2026-48736, GHSA-38cx-cq6f-5755, UBUNTU-CVE-2026-48736 ## What is CVE-2026-48736? CVE-2026-48736 is a medium-severity server-side request forgery vulnerability in Sensiolabs Symfony, published on 14 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim. ### Official 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. Weakness: CWE-918 (Server-Side Request Forgery), CWE-184 (Incomplete List of Disallowed Inputs) ## Which versions are affected by CVE-2026-48736? 16 open source packages ship an affected version, including symfony/symfony, symfony/http-client and symfony/http-foundation. It affects 1 product. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `symfony/symfony` | Packagist | From 5.4.0 | 5.4.53 | | `symfony/symfony` | Packagist | From 5.4.0 | 5.4.53 | | `symfony/symfony` | Packagist | From 6.4.0 | 6.4.41 | | `symfony/symfony` | Packagist | From 6.4.0 | 6.4.41 | | `symfony/symfony` | Packagist | From 7.0.0 | 7.4.13 | | `symfony/symfony` | Packagist | From 7.0.0 | 7.4.13 | | `symfony/symfony` | Packagist | From 8.0.0 | 8.0.13 | | `symfony/symfony` | Packagist | From 8.0.0 | 8.0.13 | | `symfony/http-client` | Packagist | From 5.4.0 | 5.4.53 | | `symfony/http-client` | Packagist | From 5.4.0 | 5.4.53 | | `symfony/http-foundation` | Packagist | From 6.4.0 | 6.4.41 | | `symfony/http-foundation` | Packagist | From 6.4.0 | 6.4.41 | | `symfony/http-foundation` | Packagist | From 7.0.0 | 7.4.13 | | `symfony/http-foundation` | Packagist | From 7.0.0 | 7.4.13 | | `symfony/http-foundation` | Packagist | From 8.0.0 | 8.0.13 | | `symfony/http-foundation` | Packagist | From 8.0.0 | 8.0.13 | Products: Sensiolabs Symfony. ## How do I fix CVE-2026-48736? Upgrade symfony/symfony to a fixed version for your release line: 5.4.53, 6.4.41, 7.4.13 or 8.0.13. ## Is CVE-2026-48736 being exploited? There is no known exploitation of CVE-2026-48736 in the wild and no public exploit code. ## Other vulnerabilities in Sensiolabs Symfony - [CVE-2019-11325](https://insights.sbomify.com/CVE-2019-11325/): Improper Input Validation in Symfony (critical 9.8) - [CVE-2017-11365](https://insights.sbomify.com/CVE-2017-11365/): Symfony Incorrect Access Control (critical 9.8) - [CVE-2019-10913](https://insights.sbomify.com/CVE-2019-10913/): Invalid HTTP method overrides allow possible XSS or other attacks in Symfony (critical 9.8) - [CVE-2018-11407](https://insights.sbomify.com/CVE-2018-11407/): Symfony Authentication Bypass (critical 9.8) - [CVE-2016-2403](https://insights.sbomify.com/CVE-2016-2403/): Symfony Authentication Bypass (critical 9.8) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2026-48736 and fix it if it is affected. What it is: CVE-2026-48736 is a medium-severity server-side request forgery vulnerability in Sensiolabs Symfony, published on 14 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim. Exploitation: There is no known exploitation of CVE-2026-48736 in the wild and no public exploit code. Affected packages and fixed versions: - symfony/symfony (Packagist): affected from 5.4.0; fixed in 5.4.53 - symfony/symfony (Packagist): affected from 5.4.0; fixed in 5.4.53 - symfony/symfony (Packagist): affected from 6.4.0; fixed in 6.4.41 - symfony/symfony (Packagist): affected from 6.4.0; fixed in 6.4.41 - symfony/symfony (Packagist): affected from 7.0.0; fixed in 7.4.13 - symfony/symfony (Packagist): affected from 7.0.0; fixed in 7.4.13 - symfony/symfony (Packagist): affected from 8.0.0; fixed in 8.0.13 - symfony/symfony (Packagist): affected from 8.0.0; fixed in 8.0.13 - symfony/http-client (Packagist): affected from 5.4.0; fixed in 5.4.53 - symfony/http-client (Packagist): affected from 5.4.0; fixed in 5.4.53 - symfony/http-foundation (Packagist): affected from 6.4.0; fixed in 6.4.41 - symfony/http-foundation (Packagist): affected from 6.4.0; fixed in 6.4.41 Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2026-48736/ (Markdown: https://insights.sbomify.com/CVE-2026-48736/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-48736 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-48736 - OSV: https://osv.dev/vulnerability/CVE-2026-48736 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-48736/ Summaries are generated and may contain mistakes; the official description above is the record.