Create CVE-2021-32618.yaml (#3546)

* Create CVE-2021-32618.yaml

* Update and rename CVE-2021-32618.yaml to cves/2021/CVE-2021-32618.yaml

* matcher update

Co-authored-by: Prince Chaddha <prince@projectdiscovery.io>
Co-authored-by: sandeep <sandeep@projectdiscovery.io>

cves/2021/CVE-2021-32618.yaml

@@ -0,0 +1,28 @@
+id: CVE-2021-32618
+
+info:
+  name: Flask Open Redirect
+  author: 0x_Akoko
+  severity: medium
+  description: There is code in FS to validate that the url specified in the next parameter is either relative OR has the same netloc (network location) as the requesting URL. This check utilizes Pythons urlsplit library. However many browsers are very lenient on the kind of URL they accept and 'fill in the blanks' when presented with a possibly incomplete URL. As a concrete example - setting http://login?next=\\\github.com will pass FS's relative URL check however many browsers will gladly convert this to http://example.com.
+  reference:
+    - https://github.com/Flask-Middleware/flask-security/security/advisories/GHSA-6qmf-fj6m-686c
+    - https://github.com/Flask-Middleware/flask-security/issues/486
+    - https://nvd.nist.gov/vuln/detail/CVE-2021-32618
+  classification:
+    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
+    cvss-score: 6.10
+    cve-id: CVE-2021-32618
+    cwe-id: CWE-601
+  tags: cve,cve2021,redirect,flask
+
+requests:
+  - method: GET
+    path:
+      - '{{BaseURL}}/login?next=\\\example.com'
+
+    matchers:
+      - type: regex
+        part: header
+        regex:
+          - '(?m)^(?:Location\s*?:\s*?)(?:https?:\/\/|\/\/|\/\\\\|\/\\)?(?:[a-zA-Z0-9\-_\.@]*)example\.com\/?(\/|[^.].*)?$' # https://regex101.com/r/ZDYhFh/1