VULNERABILITY INTELLIGENCE
CVE-2026-53591
CVSS score8.6 HIGH
EPSS probability0.27%
CISA KEVNot currently listed
Published2026-07-20
Last modified2026-10-24
CVSS vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:L
Description
FreeScout is a free help desk and shared inbox built with PHP's Laravel framework. Prior to version 1.8.223, an unauthenticated attacker can inject messages into any existing support conversation by sending a single email to the helpdesk's public address with a crafted `In-Reply-To` header. No credentials, tokens, or prior access are required. The injected message is rendered in the agent UI as a legitimate customer reply, the conversation is automatically reopened, and the `last_reply_from` field is set to the attacker's identity. Version 1.8.223 contains a fix.
Weakness classification
- security-advisories@github.com: CWE-287