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.
Analysis
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Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| sensiolabs | symfony | unaffected |
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Thu, 05 Nov 2026 13:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| 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. | |
| Title | Symfony: NoPrivateNetworkHttpClient Does Not Pin the Checked IP of Cached Hosts, Letting DNS Rebinding Enumerate Internal Ports (Incomplete Fix for CVE-2024-50342) | |
| Weaknesses | CWE-367 CWE-918 |
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cvssV4_0
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Subscriptions
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MITRE
Status: PUBLISHED
Assigner: Checkmarx
Published:
Updated: 2026-11-05T12:57:35.267Z
Reserved: 2026-11-05T12:32:19.431Z
Link: CVE-2026-123119
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-11-05T13:17:07.640
Modified: 2026-11-05T13:17:07.640
Link: CVE-2026-123119
Redhat
No data.
OpenCVE Enrichment
Updated: 2026-11-05T14:45:15Z