---
id: CVE-2026-123204
title: Posta before v0.18.0 SSRF via Webhook URL
summary: >-
  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.
  Attacker…
severity: medium
cvss: 4.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N'
cvssSource: cna
cwe:
  - CWE-918
vendor: goposta
product: posta
affected:
  - posta < v0.18.0
published: '2026-11-05'
updated: '2026-11-05'
sourceUpdated: '2026-11-05T18:16:39.804Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-123204'
references:
  - url: 'https://github.com/goposta/posta/issues/282'
  - url: 'https://github.com/goposta/posta/pull/315'
  - url: >-
      https://github.com/goposta/posta/commit/6bb376b55dcfdcb979040ed42c4bf57b99e4f46a
  - url: 'https://github.com/goposta/posta/releases/tag/v0.18.0'
    label: posta v0.18.0 Release Notes
  - url: >-
      https://github.com/goposta/posta/blob/8c3cb6f89c8a992329fac21491c38aed70d05c73/internal/services/webhook/dispatcher.go#L321-L338
  - url: >-
      https://www.vulncheck.com/advisories/posta-before-0.18.0-ssrf-via-webhook-url
    label: 'VulnCheck Advisory: Posta before v0.18.0 SSRF via Webhook URL'
tags:
  - cve.org
ingestedAt: '2026-11-05T22:38:31.457Z'
---

## Overview

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.

## Affected

- `posta < v0.18.0`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.