CVE-2026-123204 Posta before v0.18.0 SSRF via Webhook URL
- Exploited in the wild
- Not known
- Fix
- None listed
What is CVE-2026-123204?
CVE-2026-123204 is a medium-severity vulnerability in goposta posta, published on 5 Nov 2026.
Official description
Posta before v0.18.0 contains a server-side request forgery vulnerability that allows authenticated users with edit rights to make the backend send POST requests to internal destinations by creating webhooks with arbitrary URLs. Attackers can target loopback, private-network or cloud metadata addresses and read delivery status codes and error strings to probe internal hosts and ports.
Weakness: CWE-918
Which versions are affected by CVE-2026-123204?
How do I fix CVE-2026-123204?
No fix has been published for CVE-2026-123204 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-123204 being exploited?
There is no known exploitation of CVE-2026-123204 in the wild and no public exploit code.
Sources
Also known as GHSA-4ghw-3mh4-pmh7.