# CVE-2026-123119: Symfony: NoPrivateNetworkHttpClient Does Not Pin the Checked IP of Cached Hosts, Letting DNS Rebinding Enumerate Internal Ports (Incomplete Fix for CVE-2024-50342)

Status: published. Published: 2026-11-05. Updated: 2026-11-05.

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.

## Remediation

- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: Checkmarx) — https://github.com/symfony/symfony/commit/ab084826b2b5db8d0b91af635fe2b5e1c4f699f9

## Affected products and versions

- sensiolabs / symfony (symfony/http-client): ≥ 0; < 5.4.56 (affected, git); ≥ 6.0.0; < 6.4.50 (affected, git); ≥ 7.0.0; < 7.4.23 (affected, git); ≥ 8.0.0; < 8.1.11 (affected, git). Source: CNA: Checkmarx

## Severity and prioritization

- CVSS 4.0: 2.3 (low); 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; source: CNA: Checkmarx

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-367, CWE-918

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/symfony/symfony/security/advisories/GHSA-c7hm-wqwp-f9v8 (CNA: Checkmarx; third-party-advisory)

- https://github.com/symfony/symfony/commit/ab084826b2b5db8d0b91af635fe2b5e1c4f699f9 (CNA: Checkmarx; patch)

## Provenance

- CNA: Checkmarx: https://www.cve.org/CVERecord?id=CVE-2026-123119; retrieved 2026-11-05; source updated 2026-11-05

Revision: ce1f5faa4690d60a81416ce860910d59064269ad387104b4ca2359adac61b79d

Canonical: https://y2.dev/cve/CVE-2026-123119

## Agent and API access

Public CVE pages, Markdown, and JSON are free to read without an account or API key.

- Public catalog: https://y2.dev/cve/index.json. Follow nextCursor with the same search, filters, sort, and limit (1–100). A null cursor marks the end.

- WebMCP: search_cve_disclosures, get_cve_disclosure, get_cve_page_markdown, get_y2_cve_access. Available in compatible browsers.

- Cyber API: https://api.y2.dev/api/v2/cyber/cves and https://api.y2.dev/api/v2/cyber/cves/{cveId}.

- Y2 Pro or Elite: create a workspace API key with the intel:cyber scope and send Authorization: Bearer <Y2_API_KEY>. Setup: https://y2.dev/docs/api/create-key.

- x402: Pay per request without an account or API key. Omit Authorization, read the HTTP 402 PAYMENT-REQUIRED challenge, validate its current requirements, and retry with PAYMENT-SIGNATURE through an authorized payment client. These browser tools never make payments. Guide: https://y2.dev/docs/api/x402.

- OpenAPI: https://y2.dev/api/openapi.yaml. Agent access metadata: https://y2.dev/cve/agent.json.

Collected public records only. Check source status for coverage and freshness.