CVE-2025-1521
PostHog Slack Incoming Webhook SSRF Information Disclosure
Description
PostHog slack_incoming_webhook Server-Side Request Forgery Information Disclosure Vulnerability. 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. Was ZDI-CAN-25352.
INFO
Published Date :
April 23, 2025, 5:16 p.m.
Last Modified :
Aug. 7, 2025, 6:19 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.0 | HIGH | [email protected] | ||||
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Update PostHog to the latest version available.
- Review and sanitize all user-supplied URI inputs.
- Implement strict allow-lists for target URIs.
- Validate slack_incoming_webhook parameter rigorously.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2025-1521.
| URL | Resource |
|---|---|
| https://github.com/PostHog/posthog/commit/6e8f035f9acd339c5ba87ba6ea40fc1ab3053d42 | Patch |
| https://www.zerodayinitiative.com/advisories/ZDI-25-096/ | Third Party Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2025-1521 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2025-1521
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2025-1521 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2025-1521 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Aug. 07, 2025
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N Added CPE Configuration OR *cpe:2.3:a:posthog:posthog:*:*:*:*:*:*:*:* versions up to (excluding) 0.3.7 Added Reference Type Zero Day Initiative: https://github.com/PostHog/posthog/commit/6e8f035f9acd339c5ba87ba6ea40fc1ab3053d42 Types: Patch Added Reference Type Zero Day Initiative: https://www.zerodayinitiative.com/advisories/ZDI-25-096/ Types: Third Party Advisory -
New CVE Received by [email protected]
Apr. 23, 2025
Action Type Old Value New Value Added Description PostHog slack_incoming_webhook Server-Side Request Forgery Information Disclosure Vulnerability. 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. Was ZDI-CAN-25352. Added CVSS V3 AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N Added CWE CWE-918 Added Reference https://github.com/PostHog/posthog/commit/6e8f035f9acd339c5ba87ba6ea40fc1ab3053d42 Added Reference https://www.zerodayinitiative.com/advisories/ZDI-25-096/