🛡️ CVE-2026-53591

🟠 CVSS 8.6 — High ✅ No Known Exploit CWE-287 NVD
8.6
CVSS Score
0 Low4 Medium7 High9 Critical10

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.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality low, integrity high, availability low.

Weakness class

CVE-2026-53591 is classified as CWE-287: Improper Authentication. The identity of the caller is not established correctly, so an attacker can act as another user.

Affected software

CVE-2026-53591 is recorded against 1 package.

  • unknown

Timeline and source

Published on 20 July 2026 and last revised on 21 July 2026. No public exploit is currently recorded for this entry. Record sourced from NVD.

References

github.com
github.com

Details

Severity HIGH
CVSS Score 8.6
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:L
CWE CWE-287
Public Exploit ✅ No
Source NVD
Published 2026-07-20
Updated 2026-08-11
Modified 2026-07-21
Fix URL N/A

Affected Packages

Software From version Fixed in
unknown — —

Similar Threats

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