What is GHSA-4CC2-G9W2-FHF6?

GHSA-4CC2-G9W2-FHF6 is a medium-severity server-side request forgery (SSRF) vulnerability in zeep (pip), affecting versions >= 4.0.0, < 4.3.3. It is fixed in 4.3.3. Untrusted input controls the target URL of a server-initiated request, which may reach internal services not otherwise accessible from outside.

How severe is GHSA-4CC2-G9W2-FHF6?

GHSA-4CC2-G9W2-FHF6 has a CVSS score of 5.9 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.

Which versions of zeep are affected by GHSA-4CC2-G9W2-FHF6?

zeep (pip) versions >= 4.0.0, < 4.3.3 is affected.

Is there a fix for GHSA-4CC2-G9W2-FHF6?

Yes. GHSA-4CC2-G9W2-FHF6 is fixed in 4.3.3. Upgrade to this version or later.

Is GHSA-4CC2-G9W2-FHF6 exploitable, and should I be worried?

Whether GHSA-4CC2-G9W2-FHF6 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk.

What actually determines whether GHSA-4CC2-G9W2-FHF6 is exploitable, and how bad it is?

Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.

How do I fix GHSA-4CC2-G9W2-FHF6?

Upgrade zeep to 4.3.3 or later.

GHSA-4CC2-G9W2-FHF6 in zeep

Q: How severe is GHSA-4CC2-G9W2-FHF6?

GHSA-4CC2-G9W2-FHF6 has a CVSS score of 5.9 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.

Q: Which versions of zeep are affected by GHSA-4CC2-G9W2-FHF6?

zeep (pip) versions >= 4.0.0, < 4.3.3 is affected.

Q: Is there a fix for GHSA-4CC2-G9W2-FHF6?

Yes. GHSA-4CC2-G9W2-FHF6 is fixed in 4.3.3. Upgrade to this version or later.

Q: Is GHSA-4CC2-G9W2-FHF6 exploitable, and should I be worried?

Whether GHSA-4CC2-G9W2-FHF6 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk.

Q: What actually determines whether GHSA-4CC2-G9W2-FHF6 is exploitable, and how bad it is?

Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.

Q: How do I fix GHSA-4CC2-G9W2-FHF6?

Upgrade zeep to 4.3.3 or later.

Summary

Zeep: Server-Side Request Forgery (SSRF)

Full technical description

When parsing a WSDL or XSD document, python-zeep follows transitive references, xsd:import, xsd:include, wsdl:import, and lxml entity/DTD resolution, and will fetch http/https URLs found in those references. The Settings.forbid_external option, intended to disable this transitive remote fetching, was defined but not wired to any logic from version 4.0.0 through 4.3.2 (a regression introduced when zeep moved off defusedxml in 4.0). As a result, setting forbid_external=True had no effect, and applications that processed untrusted or attacker-influenced WSDL/XSD documents could be coerced into making server-side requests to arbitrary URLs (SSRF).

Workarounds

If you cannot upgrade to 4.3.3:

Do not load untrusted WSDL/XSD documents, and avoid loading WSDLs whose import/include targets can be influenced by untrusted input.
Vendor the schema locally: pre-fetch and review the WSDL and all of its imported schemas, then load them from local files (e.g. file:// paths) so no remote fetching occurs at parse
time.
Restrict egress at the network layer: block outbound traffic from the host/process to internal ranges and metadata endpoints (e.g. 169.254.169.254, RFC1918 ranges) so SSRF attempts
cannot reach sensitive targets.
Use a restrictive custom Transport: subclass the zeep transport and reject/allow-list URLs in load() so disallowed hosts are never fetched.

Impact

Server-Side Request Forgery (SSRF), CWE-918.

An attacker who can supply or influence the contents of a WSDL/XSD that an application loads with zeep can embed an import/include reference (e.g. <xsd:import schemaLocation="http://169.254.169.254/...">) pointing at an internal or otherwise sensitive endpoint. When zeep parses the document it transitively fetches that URL using the configured transport, causing the application to issue outbound requests to attacker-chosen destinations. This can be used to reach internal-only services, cloud metadata endpoints, or other hosts not directly reachable by the attacker, and may disclose response timing/behaviour.

Impacted users are those who:

load WSDL/XSD documents that are untrusted or whose import targets an attacker can control, and/or
relied on forbid_external=True as a security control, in 4.0.0–4.3.2 that setting silently did nothing, so the protection users believed they had was not in effect.

Note the default was (and remains) forbid_external=False, i.e. transitive remote fetching is permitted by default; the security defect is specifically that the opt-out control was non-functional.

Untrusted input controls the target URL of a server-initiated request, which may reach internal services not otherwise accessible from outside. Typical impact: access to internal metadata services, internal APIs, or cloud credentials.

GHSA-4CC2-G9W2-FHF6 has a CVSS score of 5.9 (Medium). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (4.3.3); upgrading removes the vulnerable code path.

Affected versions

zeep (>= 4.0.0, < 4.3.3)

Security releases

zeep → 4.3.3 (pip)

Kodem intelligence

Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.

Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.

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Remediation advice

Fixed in python-zeep 4.3.3. The forbid_external setting is now enforced: when set to True, zeep refuses to transitively fetch http/https resources via xsd:import, xsd:include, wsdl:import, or lxml entity/DTD resolution, raising zeep.exceptions.ExternalReferenceForbidden. The user-supplied entry-point WSDL/schema URL is still loaded.

Affected versions: >= 4.0.0, < 4.3.3.

Upgrade to 4.3.3 (or later) and set forbid_external=True when loading documents from untrusted sources:

from zeep import Client, Settings

settings = Settings(forbid_external=True)
client = Client("https://untrusted.example/service?wsdl", settings=settings)

Frequently Asked Questions

What is GHSA-4CC2-G9W2-FHF6? GHSA-4CC2-G9W2-FHF6 is a medium-severity server-side request forgery (SSRF) vulnerability in zeep (pip), affecting versions >= 4.0.0, < 4.3.3. It is fixed in 4.3.3. Untrusted input controls the target URL of a server-initiated request, which may reach internal services not otherwise accessible from outside.
How severe is GHSA-4CC2-G9W2-FHF6? GHSA-4CC2-G9W2-FHF6 has a CVSS score of 5.9 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
Which versions of zeep are affected by GHSA-4CC2-G9W2-FHF6? zeep (pip) versions >= 4.0.0, < 4.3.3 is affected.
Is there a fix for GHSA-4CC2-G9W2-FHF6? Yes. GHSA-4CC2-G9W2-FHF6 is fixed in 4.3.3. Upgrade to this version or later.
Is GHSA-4CC2-G9W2-FHF6 exploitable, and should I be worried? Whether GHSA-4CC2-G9W2-FHF6 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
What actually determines whether GHSA-4CC2-G9W2-FHF6 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
How do I fix GHSA-4CC2-G9W2-FHF6? Upgrade zeep to 4.3.3 or later.