FreeScout up to 1.8.222 last_reply_from injection

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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5.1$0-$5k1.69-

Summaryinfo

A vulnerability, which was classified as problematic, has been found in FreeScout up to 1.8.222. This affects an unknown part. Performing a manipulation of the argument last_reply_from results in injection. This vulnerability is known as CVE-2026-53591. Remote exploitation of the attack is possible. No exploit is available.

Detailsinfo

A vulnerability classified as problematic has been found in FreeScout up to 1.8.222. This affects an unknown functionality. The manipulation of the argument last_reply_from with an unknown input leads to a injection vulnerability. CWE is classifying the issue as CWE-74. The product constructs all or part of a command, data structure, or record using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify how it is parsed or interpreted when it is sent to a downstream component. This is going to have an impact on integrity. The summary by CVE is:

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.

The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2026-53591 since 06/09/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1055 for this issue.

Upgrading to version 1.8.223 eliminates this vulnerability.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.3
VulDB Meta Temp Score: 5.1

VulDB Base Score: 5.3
VulDB Temp Score: 5.1
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Injection
CWE: CWE-74 / CWE-707 / CWE-20
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Upgrade: FreeScout 1.8.223

Timelineinfo

06/09/2026 CVE reserved
07/20/2026 +41 days Advisory disclosed
07/20/2026 +0 days VulDB entry created
07/20/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: github.com
Status: Confirmed

CVE: CVE-2026-53591 (🔒)
GCVE (CVE): GCVE-0-2026-53591
GCVE (VulDB): GCVE-100-380745

Entryinfo

Created: 07/20/2026 22:11
Changes: 07/20/2026 22:11 (52)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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