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Full vulnerability report · 2026
CVE-2026-40498High confidence

FreeScout has Authentication Bypass and Information Disclosure in SystemController via /system/cron

freescout-help-desk · freescout

Official source article: GitHub GHSA-5JW5-Q9J7-4RXC ↗. Check the applicable product and release in the original source.

8.9HighCVSS 4.0
Recommended action
Within 7 days

High technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance.

Patch available
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityHighOperational priority:Critical, raised one band.upgradedsince 21 Apr 2026

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • A structured source references public exploit or proof-of-concept material.
  • The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
  • EPSS is 0.73% for the current model date.

Compensating controls

  • Validate the affected product branch and deploy the verified fixed release.
  • Restrict the affected network interface to trusted sources where business-safe.
  • Increase monitoring for the attack path and post-exploitation behaviour described in the report.

Verification

  1. Confirm that the asset runs freescout-help-desk freescout and falls inside the recorded affected range.
  2. Verify the installed build against the product-specific fixed version after deployment.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: Within 3 daysRemediation target: Within 90 days

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2026-24137

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 7 days

High technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance.

Patch available
01

What, why and how

FreeScout is a free self-hosted help desk and shared mailbox. Prior to version 1.8.213, an unauthenticated attacker can access diagnostic and system tools that should be restricted to administrators. The /system/cron endpoint relies on a static MD5 hash derived from the APP_KEY, which is exposed in the response and logs. Accessing these endpoints reveals sensitive server information (Full Path Disclosure), process IDs, and allows for Resource Exhaustion (DoS) by triggering heavy background tasks repeatedly without any rate limiting. The cron hash is generated using md5(APP_KEY . 'web_cron_hash'). Since this hash is often transmitted via GET requests, it is susceptible to exposure in server logs, browser history, and proxy logs. Furthermore, the lack of rate limiting on these endpoints allows for automated resource exhaustion (DoS) and brute-force attempts. Version 1.8.213 fixes the issue.

What

FreeScout is a free self-hosted help desk and shared mailbox. Prior to version 1.8.213, an unauthenticated attacker can access diagnostic and system tools that should be restricted to administrators. The /system/cron endpoint relies on a static MD5 hash derived from the APP_KEY, which is exposed in the response and logs. Accessing these endpoints reveals sensitive server information (Full Path Disclosure), process IDs, and allows for Resource Exhaustion (DoS) by triggering heavy background tasks repeatedly without any rate limiting. The cron hash is generated using md5(APP_KEY . 'web_cron_hash'). Since this hash is often transmitted via GET requests, it is susceptible to exposure in server logs, browser history, and proxy logs. Furthermore, the lack of rate limiting on these endpoints allows for automated resource exhaustion (DoS) and brute-force attempts. Version 1.8.213 fixes the issue.

Why

The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may disrupt the affected service.

What

FreeScout is a free self-hosted help desk and shared mailbox. Prior to version 1.8.213, an unauthenticated attacker can access diagnostic and system tools that should be restricted to administrators. The /system/cron endpoint relies on a static MD5 hash derived from the APP_KEY, which is exposed in the response and logs. Accessing these endpoints reveals sensitive server information (Full Path Disclosure), process IDs, and allows for Resource Exhaustion (DoS) by triggering heavy background tasks repeatedly without any rate limiting. The cron hash is generated using md5(APP_KEY . 'web_cron_hash'). Since this hash is often transmitted via GET requests, it is susceptible to exposure in server logs, browser history, and proxy logs. Furthermore, the lack of rate limiting on these endpoints allows for automated resource exhaustion (DoS) and brute-force attempts. Version 1.8.213 fixes the issue.

Why

The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may disrupt the affected service.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
Reference recorded

A structured CVE source labels at least one public reference as exploit material. BlackTree has not independently validated that it is safe, reliable or weaponised.

Likely attack path
a network path → Exposure of Sensitive Information to an Unauthorized Actor → disrupt the affected service
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Not a CVSS 4.0 base metric
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-200 ↗

CWE-200: Exposure of Sensitive Information to an Unauthorized Actor. The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N/E:P

Common Vulnerability Scoring System 4.0: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.ATNoneAttack requirements: No additional deployment or execution condition is required.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.VCHighVulnerable-system confidentiality: A successful attack can cause a major loss.VIHighVulnerable-system integrity: A successful attack can cause a major loss.VALowVulnerable-system availability: A successful attack can cause a limited loss.SCNoneSubsequent-system confidentiality: No direct loss is represented by this metric.SINoneSubsequent-system integrity: No direct loss is represented by this metric.SANoneSubsequent-system availability: No direct loss is represented by this metric.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkUnauthenticatedDenial of serviceCWE-200Public exploit reference
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

Cyber Security Agency of Singapore · English · CSA-SB-20260422Security Bulletin 22 April 2026

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 22 April 2026, published on 22 April 2026. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2026-012471FreeScoutにおける複数の脆弱性

FreeScoutは無料のセルフホステッド型ヘルプデスクおよび共有メールボックスです。バージョン1.8.213以前では、認証されていない攻撃者が管理者に制限されるべき診断およびシステムツールにアクセスできてしまいました。/system/cronエンドポイントはAPP_KEYから派生した静的なMD5ハッシュに依存しており、このハッシュはレスポンスやログに露出します。これらのエンドポイントにアクセスすると、機密性の高いサーバー情報（フルパス情報漏えい）やプロセスIDが判明します。また、レート制限なしに重いバックグラウンドタスクを繰り返し起動することで、リソース枯渇（DoS攻撃）を引き起こすことが可能です。cronハッシュはmd5(APP_KEY . 'web_cron_hash')で生成されます。このハッシュはGETリクエストを介して送信されることが多く、サーバーログ、ブラウザ履歴、プロキシログで露出する恐れがあります。さらに、これらのエンドポイントに対するレート制限の欠如により、自動化されたリソース枯渇（DoS）やブルートフォース攻撃が可能になります。バージョン1.8.213でこの問題は修正されました。

Official advisory ↗
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Patch available
Affected
freescout: < 1.8.213
Fixed
An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
Action
Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04

Evidence and provenance

Published 21 Apr 2026 · Last source change 21 Apr 2026, 19:20 UTC · CWE-200 · Exposure of Sensitive Information to an Unauthorized Actor

CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2026-24137
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD enriched

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates ↗

No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.

Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Fixed release or patch reference recorded
ENISA EUVD · EUVD-2026-24137↗CISA Vulnrichment SSVC evidence↗Public exploit reference · GitHub GHSA-5JW5-Q9J7-4RXC↗Patch or update reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2026-40498 · cve.blacktree.nl