# CVE-2026-123119: The Symfony HttpClient component NoPrivateNetworkHttpClient does not pin the checked IP address of cached hosts, allowing for DNS rebinding


- **Severity:** Low 2.3 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:N/SC:L/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 5 Nov 2026
- **Updated:** 5 Nov 2026
- **Also known as:** DEBIAN-CVE-2026-123119, GHSA-c7hm-wqwp-f9v8, UBUNTU-CVE-2026-123119

## What is CVE-2026-123119?

CVE-2026-123119 is a low-severity vulnerability in sensiolabs symfony, published on 5 Nov 2026. 

### Official description

The Symfony HttpClient component NoPrivateNetworkHttpClient does not pin the checked IP address of cached hosts, allowing for DNS rebinding to bypass private network restrictions, resulting in enumeration of internal hosts and ports 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.

NoPrivateNetworkHttpClient resolves the host of each request and checks the IP before connecting. It caches the result per host, and passes the IP to the decorated client through the resolve option so that the client connects to the exact IP that was checked. The issue is that resolve was only passed on the first lookup of a host: on subsequent requests, the decorated client resolved the host again on its own.

An attacker who controls a host's DNS can exploit this with DNS rebinding by answering the first lookup with a public IP, and subsequent lookups with a private IP, so when an application sends several requests to that host through the same client, the later requests connect to the private IP. This happens, for example, when an application fetches several URLs of a repository provided by a user. The check of the primary_ip in the on_progress callback still aborts the request before anything is sent, but the connection is made, and the error differs depending on whether the port is open or closed. This allows enumerating internal hosts and ports, as in CVE-2024-50342.

Weakness: CWE-918 (Server-Side Request Forgery), CWE-367 (Time-of-check Time-of-use (TOCTOU) Race Condition)

## Which versions are affected by CVE-2026-123119?


## How do I fix CVE-2026-123119?

Upgrade to a fixed version.

## Is CVE-2026-123119 being exploited?

There is no known exploitation of CVE-2026-123119 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-123119 and fix it if it is affected.

What it is: CVE-2026-123119 is a low-severity vulnerability in sensiolabs symfony, published on 5 Nov 2026. 
Exploitation: There is no known exploitation of CVE-2026-123119 in the wild and no public exploit code.

Affected product: sensiolabs symfony. No package-level version data is available, so check the vendor advisory linked from the reference page.

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-2026-123119/ (Markdown: https://insights.sbomify.com/CVE-2026-123119/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-123119
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-123119
- OSV: https://osv.dev/vulnerability/CVE-2026-123119

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-123119/
Summaries are generated and may contain mistakes; the official description above is the record.