8.6

CVE-2026-53591

FreeScout Vulnerable to Unauthenticated Conversation Thread Injection via HMAC Length Bypass in FetchEmails

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.
Daten sind bereitgestellt durch das CVE Programm von einer CVE Numbering Authority (CNA) (Unstrukturiert).
Herstellerfreescout-help-desk
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Produkt freescout
Version < 1.8.223
Status affected
VulnDex Vulnerability Enrichment
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Zu dieser CVE wurde keine Warnung gefunden.
EPSS Metriken
Typ Quelle Score Percentile
EPSS FIRST.org 0.22% 0.12
CVSS Metriken
Quelle Base Score Exploit Score Impact Score Vector String
security-advisories@github.com 8.6 3.9 4.7
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:L
CWE-287 Improper Authentication

When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.

https://github.com/freescout-help-desk/freescout/security/advisories/GHSA-8vm3-wwq4-ggfx