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Full vulnerability report · 2026
CVE-2026-39808High confidence

Fortinet FortiSandbox OS Command Injection Vulnerability

Fortinet · FortiSandbox

Official source article: Fortinet FG-IR-26-100 ↗. Check the applicable product and release in the original source.

9.1CriticalCVSS 3.1
Recommended action
Patch now

CISA confirms exploitation in the wild and lists 2026-07-19 as the remediation due date.

Patch available
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityCriticalOperational priority:Critical, unchanged from published severity.unchanged

Evidence used

  • CISA confirms exploitation in the wild.
  • 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 47.36% 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 Fortinet FortiSandbox 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-2026-22338

CISA KEV mirrored by ENISA

A improper neutralization of special elements used in an os command ('os command injection') vulnerability in Fortinet FortiSandbox 4.4.0 through 4.4.8 may allow attacker to execute unauthorized code or commands via <insert attack vector here>

EUVD state
Present in the current official mapping
Known exploitation
Recorded by ENISA since 16 Jul 2026. Evidence sources: cisa_kev.
ENISA score
9.1 · CVSS 3.1
Advisory evidence
1 linked advisory record
Explicit mitigation evidence

Only statements that explicitly mention a fix, patch, update, workaround or mitigation are shown here.

  • csaf_ncscnl · NCSC-2026-0121Kwetsbaarheden verholpen in Fortinet FortiSandbox
Recommended actionPatch now

CISA confirms exploitation in the wild and lists 2026-07-19 as the remediation due date.

Patch available
01

What, why and how

Fortinet FortiSandbox contains an OS command injection vulnerability that could allow an unauthenticated attacker to execute unauthorized code or commands via crafted HTTP requests.

What

Fortinet FortiSandbox contains an OS command injection vulnerability that could allow an unauthenticated attacker to execute unauthorized code or commands via crafted HTTP requests.

Why

Untrusted input is incorporated into an operating-system command without safe parameter handling.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

Fortinet FortiSandbox contains an OS command injection vulnerability that could allow an unauthenticated attacker to execute unauthorized code or commands via crafted HTTP requests.

Why

Untrusted input is incorporated into an operating-system command without safe parameter handling.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

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.
Confirmed in the wild

CISA added this CVE to its Known Exploited Vulnerabilities catalogue on 2026-07-16.

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 → Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-78 ↗

CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection'). The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C

Common Vulnerability Scoring System 3.1: 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.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CHighConfidentiality impact: A successful attack can cause a major loss.IHighIntegrity impact: A successful attack can cause a major loss.AHighAvailability impact: A successful attack can cause a major loss.
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.
NetworkUnauthenticatedCWE-78CISA KEVPublic exploit reference
A

Official authority intelligence

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

ENISA EUVD · EUVD-2026-22338Known-exploited evidence recorded

A improper neutralization of special elements used in an os command ('os command injection') vulnerability in Fortinet FortiSandbox 4.4.0 through 4.4.8 may allow attacker to execute unauthorized code or commands via <insert attack vector here>

Official EUVD record ↗
BSI · German · WID-SEC-2026-1094Fortinet FortiSandbox: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in Fortinet FortiSandbox ausnutzen, um einen Cross-Site Scripting Angriff durchzuführen, Informationen offenzulegen, Sicherheitsmaßnahmen zu umgehen und Code zur Ausführung zu bringen.

Official advisory ↗
Canadian Centre for Cyber Security · English · AV26-351Fortinet security advisory (AV26-351) – Update 2

On April 14, 2026, Fortinet published security advisories to address vulnerabilities in multiple products. Included were critical updates for the following: Open-source reporting indicates that CVE-2026-39813, CVE-2026-39808, and CVE-2026-25089 have been exploited.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20260415Security Bulletin 15 April 2026

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 15 April 2026, published on 15 April 2026. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2026-AVI-0440Multiples vulnérabilités dans les produits Fortinet

d?id=CVE-2026-22154 Référence CVE CVE-2026-22155 https://www.cve.org/CVERecord?id=CVE-2026-22155 Référence CVE CVE-2026-22573 https://www.cve.org/CVERecord?id=CVE-2026-22573 Référence CVE CVE-2026-22574 https://www.cve.org/CVERecord?id=CVE-2026-22574 Référence CVE CVE-2026-22576 https://www.cve.org/CVERecord?id=CVE-2026-22576 Référence CVE CVE-2026-22828 https://www.cve.org/CVERecord?id=CVE-2026-22828 Référence CVE CVE-2026-23708 https://www.cve.org/CVERecord?id=CVE-2026-23708 Référence CVE CVE-2026-25691 https://www.cve.org/CVERecord?id=CVE-2026-25691 Référence CVE CVE-2026-27316 https://www.cve.org/CVERecord?id=CVE-2026-27316 Référence CVE CVE-2026-39808 https://www.cve.org/CVERecord?id=CVE-2026-39808 Référence CVE CVE-2026-39809 https://www.cve.org/CVERecord?id=CVE-2026-39809 Référence CVE CVE-2026-39810 https://www.cve.org/CVERecord?id=CVE-2026-39810 Référence CVE CVE-2026-39811 https://www.cve.org/CVERecord?id=CVE-2026-39811 Référence CVE CVE-2026-39812 https://www.cve.org/CVERecord?id=CVE-2026-39812 Référence CVE CVE-2026-39813 https://www.cve.org/CVERecord?id=CVE-2026-39813 Référence CVE CVE-2026-39814 https://www.cve.org/CVERecord?id=CVE-2026-39814 Référence CVE CVE-2026-39815 https://www.cve.org/CVERecord?id=CVE-2026-39815 Référence CVE CVE-2026-40688 https://www.cve.org/CVERecord?id=

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2026-011925フォーティネットのFortiSandboxにおけるOS コマンドインジェクションの脆弱性

Fortinet FortiSandbox 4.4.0から4.4.8にかけて、OSコマンドインジェクションで使用される特殊要素の不適切な無害化により、攻撃者が挿入攻撃ベクターここを介して不正なコードまたはコマンドを実行できる可能性があります。

Official advisory ↗
KISA KrCERT/CC · Korean · KNVD-6885美 CISA 발표 주요 Exploit 정보공유(Update. 2026-07-16)

Fortinet FortiSandbox OS Command Injection Vulnerability

Official advisory ↗
KISA KrCERT/CC · Korean · KNVD-6852Fortinet 제품 보안 업데이트 권고

FortiSandbox에서 발생하는 OS Command Injection 취약점(CVE-2026-39808) [2][5]

Official advisory ↗
NCSC-NL · Dutch · NCSC-2026-0121Kwetsbaarheden verholpen in Fortinet FortiSandbox

Een kwaadwillende kan de kwetsbaarheden met kenmerk CVE-2026-39813 en CVE-2026-39808 misbruiken doordat in FortiSandbox sprake is van OS command injection en een path traversal-kwetsbaarheid in de JRPC API. Hierdoor kan een niet-geauthenticeerde aanvaller via gemanipuleerde HTTP-verzoeken ongeautoriseerde code of commando’s uitvoeren en authenticatie omzeilen. De overige kwetsbaarheden omvatten een path traversal-kwetsbaarheid waardoor een geprivilegieerde super-admin met CLI-toegang via HTTP-verzoeken mappen kan verwijderen, en meerdere cross-site scripting kwetsbaarheden (reflected en stored) waardoor via gemanipuleerde HTTP-verzoeken XSS-aanvallen kunnen worden uitgevoerd.

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
Fixed
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 14 Apr 2026 · Last source change 17 Jul 2026, 03:56 UTC · CWE-78 · Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

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-2026-22338
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 ↗
  1. BlackTree coverageBlackTree article coverage changed from no BlackTree article to 1 BlackTree article.
    Before
    no BlackTree article
    After
    1 BlackTree article
    BlackTree editorial ↗
  2. Vendor guidanceAuthoritative vendor guidance changed: added remediation: fortiguard.fortinet.com/FG-IR-26-100.
    Before
    vendor advisory: fortiguard.fortinet.com/FG-IR-26-100
    After
    remediation: fortiguard.fortinet.com/FG-IR-26-100 · vendor advisory: fortiguard.fortinet.com/FG-IR-26-100
    psirt@fortinet.com ↗
  3. Affected versionsThe structured affected or fixed version information changed.
    Before
    4.4.0 ≤ 4.4.8; 23.4.4374; 23.4.4350; 23.3.4329; 23.1.4245; 22.2.4151; 22.2.4134; 22.1.4113 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    After
    FortiSandbox: 4.4.0 ≤ 4.4.8; FortiSandbox PaaS: 23.4.4374, 23.4.4350, 23.3.4329, 23.1.4245, 22.2.4151, 22.2.4134, 22.1.4113, 21.4.4072, 21.3.4055 · Fixed: Upgrade to FortiSandbox version 4.4.9 or above; Upgrade to FortiSandbox PaaS version 5.0.2 or above
    CNA ↗
  4. Remediation statusRemediation status changed from Awaiting fix to Patch available.
    Before
    Awaiting fix
    After
    Patch available
    psirt@fortinet.com ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Added to CISA KEV
Fixed release or patch reference recorded
ENISA EUVD · EUVD-2026-22338↗CISA KEV record↗CVE authority or vendor reference · Fortinet FG-IR-26-100↗Public exploit 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-2026-39808 · cve.blacktree.nl