Advisory Details

February 25th, 2025

PostHog slack_incoming_webhook Server-Side Request Forgery Information Disclosure Vulnerability

ZDI-25-096
ZDI-CAN-25352

CVE ID CVE-2025-1521
CVSS SCORE 7.1, AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N
AFFECTED VENDORS PostHog
AFFECTED PRODUCTS PostHog
VULNERABILITY DETAILS

This vulnerability allows remote attackers to disclose sensitive information on affected installations of PostHog. Authentication is required to exploit this vulnerability.

The specific flaw exists within the processing of the slack_incoming_webhook parameter. The issue results from the lack of proper validation of a URI prior to accessing resources. An attacker can leverage this vulnerability to execute code in the context of the service account.
ADDITIONAL DETAILS PostHog has issued an update to correct this vulnerability. More details can be found at:
https://github.com/PostHog/posthog/commit/6e8f035f9acd339c5ba87ba6ea40fc1ab3053d42
DISCLOSURE TIMELINE
  • 2024-10-03 - Vulnerability reported to vendor
  • 2025-02-25 - Coordinated public release of advisory
  • 2025-02-25 - Advisory Updated
CREDIT Mehmet INCE (@mdisec) from PRODAFT.com
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