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CVE-2026-33752 — Redirect-based SSRF leading to internal network access in curl_cffi (with TLS impersonation bypass)

Affected: lexiforest curl_cffi

curl_cffi is the a Python binding for curl. Prior to 0.15.0, curl_cffi does not restrict requests to internal IP ranges, and follows redirects automatically via the underlying libcurl. Because of this, an attacker-controlled URL can redirect requests to internal services such as cloud metadata endpoints. In addition, curl_cffi’s TLS impersonation feature can make these requests appear as legitimate browser traffic, which may bypass certain network controls. This vulnerability is fixed in 0.15.0.

GHSA-qw2m-4pqf-rmpp — curl_cffi: Redirect-based SSRF leads to internal network access in curl_cffi (with TLS impersonation bypass)

Affected: PyPI: curl_cffi

### Summary curl_cffi does not restrict requests to internal IP ranges, and follows redirects automatically via the underlying libcurl.

Because of this, an attacker-controlled URL can redirect requests to internal services such as cloud metadata endpoints. In addition, curl_cffi’s TLS impersonation feature can make these requests appear as legitimate browser traffic, which may bypass certain network controls.

### Details The issue comes from how curl_cffi handles outbound requests - User-supplied URLs are passed directly to libcurl without checking whether they resolve to internal IP ranges (e.g., 127.0.0.1, 169.254.0.0/16). - Redirects are automatically followed (CURLOPT_FOLLOWLOCATION = 1) inside libcurl. - There is no validation of redirect destinations at the Python layer.

This means that even if an application only allows requests to external URLs, an attacker can - Provide a URL pointing to an attacker-controlled server - Return a redirect response pointing to an internal service - Have curl_cffi follow that redirect automatically

As a result, internal endpoints (such as cloud instance metadata APIs) can be accessed.

Additionally, curl_cffi supports TLS fingerprint impersonation (e.g., impersonate="chrome"). In environments where outbound requests are filtered based on TLS fingerprinting, this can make such requests harder to detect or block

This behavior is similar to previously reported redirect-based SSRF issues such as CVE-2025-68616, where redirects allowed…

PYSEC-2026-2431 — curl_cffi: Redirect-based SSRF leads to internal network access in curl_cffi (with TLS impersonation bypass)

Affected: PyPI: curl-cffi

### Summary curl_cffi does not restrict requests to internal IP ranges, and follows redirects automatically via the underlying libcurl.

As a result, internal endpoints (such as cloud instance metadata APIs) can be accessed.

This behavior is similar to previously reported redirect-based SSRF issues such as CVE-2025-68616, where redirects allowed…