#VU104202 Server-Side Request Forgery (SSRF) in PostHog - CVE-2025-1521

Vulnerability identifier: #VU104202

Vulnerability risk: Medium

CVSSv4.0: 2.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:H/SI:L/SA:N/E:U/U:Green]

CVE-ID: CVE-2025-1521

CWE-ID: CWE-918

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
PostHog
Web applications / Other software

Vendor: PostHog

Description

The disclosed vulnerability allows a remote attacker to perform SSRF attacks.

The vulnerability exists due to insufficient validation of user-supplied input within the processing of the slack_incoming_webhook parameter. A remote user can send a specially crafted HTTP request and trick the application to initiate requests to arbitrary systems.

Successful exploitation of this vulnerability may allow a remote attacker gain access to sensitive data, located in the local network or send malicious requests to other servers from the vulnerable system.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

PostHog: All versions

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External links
https://www.zerodayinitiative.com/advisories/ZDI-25-096/

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.