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Full vulnerability report · 2026
CVE-2026-20341High confidence

Cisco Secure Firewall Management Center Software sftunnel Deserialization Root Command Execution Vulnerability

Cisco · Cisco Secure Firewall Management Center (FMC)

Official source article: Cisco CISCO-SA-FMC-MULIVULNS-4PSNFWVX ↗. Check the applicable product and release in the original source.

9.1CriticalCVSS 3.1
Recommended action
Patch only the product branches with a verified fix

Critical technical severity; prioritise exposed affected systems while verifying vendor guidance. Verified remediation exists for at least one product or source, but 68 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Fix availability varies by product
R
Operational reassessment

Published severity in operational context

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

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • EPSS is 0.45% 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.
  • Monitor vendor guidance and exploitation sources for a material change.

Verification

  1. Confirm that the asset runs Cisco Cisco Secure Firewall Management Center (FMC) 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.

Cross-source reconciliation

Remediation availability differs by product scope

Verified remediation exists for at least one product or source, but 68 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Direct vendor intelligence

Authoritative vendor CSAF and VEX advisories

Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.

1 current
cisco-sa-fmc-mulivulns-4PsnFwvx · CSAF 2.0 · revision 1.0.0 · finalCisco PSIRTCisco Secure Firewall Management Center Software sftunnel Deserialization Root Command Execution Vulnerability
68 known affected

The vendor explicitly identifies these products as affected by this CVE.

  • Cisco Secure Firewall Management Center (FMC) 7.0.0 when installed on Cisco Secure Firewall Management Center (FMC) Appliances
  • Cisco Secure Firewall Management Center (FMC) 7.0.0.1 when installed on Cisco Secure Firewall Management Center (FMC) Appliances
  • Cisco Secure Firewall Management Center (FMC) 7.0.1 when installed on Cisco Secure Firewall Management Center (FMC) Appliances
  • Cisco Secure Firewall Management Center (FMC) 7.0.1.1 when installed on Cisco Secure Firewall Management Center (FMC) Appliances
  • Cisco Secure Firewall Management Center (FMC) 7.0.2 when installed on Cisco Secure Firewall Management Center (FMC) Appliances
  • Cisco Secure Firewall Management Center (FMC) 7.2.0 when installed on Cisco Secure Firewall Management Center (FMC) Appliances
  • Cisco Secure Firewall Management Center (FMC) 7.0.2.1 when installed on Cisco Secure Firewall Management Center (FMC) Appliances
  • Cisco Secure Firewall Management Center (FMC) 7.0.3 when installed on Cisco Secure Firewall Management Center (FMC) Appliances
  • Cisco Secure Firewall Management Center (FMC) 7.2.1 when installed on Cisco Secure Firewall Management Center (FMC) Appliances
  • Cisco Secure Firewall Management Center (FMC) 7.0.4 when installed on Cisco Secure Firewall Management Center (FMC) Appliances
  • Cisco Secure Firewall Management Center (FMC) 7.0.5 when installed on Cisco Secure Firewall Management Center (FMC) Appliances
  • Cisco Secure Firewall Management Center (FMC) 7.3.0 when installed on Cisco Secure Firewall Management Center (FMC) Appliances
Summary
Complete.
Remediation
Cisco has released software updates that address this vulnerability.
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-2026-81110

No EUVD known-exploited evidence

A vulnerability in the sftunnel inter-device communication protocol of Cisco Secure FMC Software could allow an authenticated, remote attacker to obtain root privileges. This vulnerability is due to unsecured deserialization of untrusted data over the sftunnel management connection. An attacker could exploit this vulnerability by sending crafted sftunnel remote procedure calls (RPCs). A successful exploit could allow the attacker to gain root privileges on a device that is running Cisco Secure FMC Software and its high-availability peer. To exploit this vulnerability, the attacker must have valid administrative credentials on a managed Cisco FTD device.

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
9.1 · CVSS 3.1
Advisory evidence
No linked advisory details stored yet
Recommended actionPatch only the product branches with a verified fix

Critical technical severity; prioritise exposed affected systems while verifying vendor guidance. Verified remediation exists for at least one product or source, but 68 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Fix availability varies by product
01

What, why and how

A vulnerability in the sftunnel inter-device communication protocol of Cisco Secure FMC Software could allow an authenticated, remote attacker to obtain root privileges. This vulnerability is due to unsecured deserialization of untrusted data over the sftunnel management connection. An attacker could exploit this vulnerability by sending crafted sftunnel remote procedure calls (RPCs). A successful exploit could allow the attacker to gain root privileges on a device that is running Cisco Secure FMC Software and its high-availability peer. To exploit this vulnerability, the attacker must have valid administrative credentials on a managed Cisco FTD device.

What

A vulnerability in the sftunnel inter-device communication protocol of Cisco Secure FMC Software could allow an authenticated, remote attacker to obtain root privileges. This vulnerability is due to unsecured deserialization of untrusted data over the sftunnel management connection. An attacker could exploit this vulnerability by sending crafted sftunnel remote procedure calls (RPCs). A successful exploit could allow the attacker to gain root privileges on a device that is running Cisco Secure FMC Software and its high-availability peer. To exploit this vulnerability, the attacker must have valid administrative credentials on a managed Cisco FTD device.

Why

Attacker-influenced serialised data is reconstructed as trusted objects, which can invoke dangerous application behaviour.

How

An attacker operating through a network path may attempt exploitation with elevated privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

A vulnerability in the sftunnel inter-device communication protocol of Cisco Secure FMC Software could allow an authenticated, remote attacker to obtain root privileges. This vulnerability is due to unsecured deserialization of untrusted data over the sftunnel management connection. An attacker could exploit this vulnerability by sending crafted sftunnel remote procedure calls (RPCs). A successful exploit could allow the attacker to gain root privileges on a device that is running Cisco Secure FMC Software and its high-availability peer. To exploit this vulnerability, the attacker must have valid administrative credentials on a managed Cisco FTD device.

Why

Attacker-influenced serialised data is reconstructed as trusted objects, which can invoke dangerous application behaviour.

How

An attacker operating through a network path may attempt exploitation with elevated privileges. 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.
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.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
a network path → Deserialization of Untrusted Data → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
High: elevated access is required
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Changed: exploitation can affect a different security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-502 ↗

CWE-502: Deserialization of Untrusted Data. The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.

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:H/UI:N/S:C/C:H/I:H/A:H

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.PRHighPrivileges required: The attacker needs elevated or administrative privileges.UINoneUser interaction: No action by another user is required.SChangedScope: The attack can affect a component governed by a different security 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
Stolen credentials, tokens and legitimate administration functions may provide continued access without deploying a large custom toolset.
NetworkCWE-502
A

Official authority intelligence

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

ENISA EUVD · EUVD-2026-81110Official EUVD mapping

A vulnerability in the sftunnel inter-device communication protocol of Cisco Secure FMC Software could allow an authenticated, remote attacker to obtain root privileges. This vulnerability is due to unsecured deserialization of untrusted data over the sftunnel management connection. An attacker could exploit this vulnerability by sending crafted sftunnel remote procedure calls (RPCs). A successful exploit could allow the attacker to gain root privileges on a device that is running Cisco Secure FMC Software and its high-availability peer. To exploit this vulnerability, the attacker must have valid administrative credentials on a managed Cisco FTD device.

Official EUVD record ↗
BSI · German · WID-SEC-2026-3417Cisco Secure Firewall Management Center: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in Cisco Secure Firewall Management Center ausnutzen, um Sicherheitsmaßnahmen zu umgehen, beliebige Befehle als Root auszuführen, Berechtigungen auf Root zu erweitern, SQL-Injection durchzuführen, Anmeldedaten für Administratorsitzungen zu erlangen, sensible Daten zu manipulieren und offenzulegen oder Denial-of-Service-Zustände herbeizuführen.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20260923Security Bulletin 23 Sep 2026

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 23 Sep 2026, published on 23 September 2026. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
INCIBE-CERT · Spanish · multiples-vulnerabilidades-en-productos-de-cisco-15Múltiples vulnerabilidades en productos de Cisco

epcionales, validación de datos estructurados, mecanismos de protección, controles de acceso, comparaciones incorrectas, incumplimiento de estándares de programación, errores de cálculo y gestión inadecuada de recursos. CVE-2026-20324 : vulnerabilidad en el protocolo de comunicación entre dispositivos sftunnel de Cisco Secure FMC. Un atacante remoto autenticado podría escribir un archivo arbitrario en cualquier ubicación del dispositivo y ejecutar comandos con privilegios de root. CVE-2026-20242 : vulnerabilidad de deserialización de Java en Cisco Secure FMC que podría permitir a un atacante remoto ejecutar código arbitrario. CVE-2026-20340, CVE-2026-20341, CVE-2026-20342, CVE-2026-20343 y CVE-2026-20344 : vulnerabilidades en Cisco Secure FMC que podrían permitir la ejecución de código, la omisión de controles de seguridad, el acceso a información sensible o la alteración del funcionamiento del dispositivo. CVE-2026-76412, CVE-2026-76413 y CVE-2026-76420 : vulnerabilidades en Cisco Secure FMC relacionadas con controles de seguridad insuficientes y el acceso no autorizado a funciones o recursos. CVE-2026-20322, CVE-2026-20325, CVE-2026-20326, CVE-2026-20360, CVE-2026-20361 y CVE-2026-76409 : agrupan vulnerabilidades en Cisco Nexus Dashboard relacionadas con controles de acceso incorrectos, inye

Official advisory ↗
CERT-FR · French · CERTFR-2026-AVI-1197Multiples vulnérabilités dans les produits Cisco

d?id=CVE-2026-20329 Référence CVE CVE-2026-20330 https://www.cve.org/CVERecord?id=CVE-2026-20330 Référence CVE CVE-2026-20331 https://www.cve.org/CVERecord?id=CVE-2026-20331 Référence CVE CVE-2026-20332 https://www.cve.org/CVERecord?id=CVE-2026-20332 Référence CVE CVE-2026-20333 https://www.cve.org/CVERecord?id=CVE-2026-20333 Référence CVE CVE-2026-20334 https://www.cve.org/CVERecord?id=CVE-2026-20334 Référence CVE CVE-2026-20335 https://www.cve.org/CVERecord?id=CVE-2026-20335 Référence CVE CVE-2026-20336 https://www.cve.org/CVERecord?id=CVE-2026-20336 Référence CVE CVE-2026-20340 https://www.cve.org/CVERecord?id=CVE-2026-20340 Référence CVE CVE-2026-20341 https://www.cve.org/CVERecord?id=CVE-2026-20341 Référence CVE CVE-2026-20342 https://www.cve.org/CVERecord?id=CVE-2026-20342 Référence CVE CVE-2026-20343 https://www.cve.org/CVERecord?id=CVE-2026-20343 Référence CVE CVE-2026-20344 https://www.cve.org/CVERecord?id=CVE-2026-20344 Référence CVE CVE-2026-20352 https://www.cve.org/CVERecord?id=CVE-2026-20352 Référence CVE CVE-2026-20360 https://www.cve.org/CVERecord?id=CVE-2026-20360 Référence CVE CVE-2026-20361 https://www.cve.org/CVERecord?id=CVE-2026-20361 Référence CVE CVE-2026-76409 https://www.cve.org/CVERecord?id=CVE-2026-76409 Référence CVE CVE-2026-76412 https://www.cve.org/CVERecord?id=

Official advisory ↗
CSIRT Italia · Italian · risolte-vulnerabilita-in-prodotti-cisco-32Risolte vulnerabilità in prodotti Cisco

EXPLOITATION CVE-2026-76460 : apre una nuova finestra - Presente CVE-2026-76425 : apre una nuova finestra - - CVE-2026-76424 : apre una nuova finestra - - CVE-2026-76423 : apre una nuova finestra - - CVE-2026-76420 : apre una nuova finestra - - CVE-2026-76413 : apre una nuova finestra - - CVE-2026-76412 : apre una nuova finestra - - CVE-2026-76409 : apre una nuova finestra - - CVE-2026-20361 : apre una nuova finestra - - CVE-2026-20360 : apre una nuova finestra - - CVE-2026-20352 : apre una nuova finestra - - CVE-2026-20344 : apre una nuova finestra - - CVE-2026-20343 : apre una nuova finestra - - CVE-2026-20342 : apre una nuova finestra - - CVE-2026-20341 : apre una nuova finestra - - CVE-2026-20340 : apre una nuova finestra - - CVE-2026-20336 : apre una nuova finestra - - CVE-2026-20335 : apre una nuova finestra - - CVE-2026-20334 : apre una nuova finestra - - CVE-2026-20333 : apre una nuova finestra - - CVE-2026-20332 : apre una nuova finestra - - CVE-2026-20331 : apre una nuova finestra - - CVE-2026-20330 : apre una nuova finestra - - CVE-2026-20329 : apre una nuova finestra - - CVE-2026-20326 : apre una nuova finestra - - CVE-2026-20325 : apre una nuova finestra - - CVE-2026-20324 : apre una nuova finestra - - CVE-2026-20323 : apre una nuova finestra - - CVE-2026-20322 : apre una nuova fi

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.
Fix availability varies by product
Affected
Fixed
No fixed version is explicitly recorded in the structured CVE data.
Action
Use the product-specific evidence above. Patch only products with a verified fixed release, and keep every affected or under-investigation state without a matching fix in the remediation queue.
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 16 Sept 2026 · Last source change 18 Sept 2026, 03:55 UTC · CWE-502 · Deserialization of Untrusted Data

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 2026-09-17
European sourceENISA EUVD · EUVD-2026-81110
Product sourceVendor CSAF · Cisco PSIRT
Remediation sourceVendor CSAF · Cisco PSIRT
CWE sourceCNA
NVD statusNVD awaiting enrichment

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

Material change intelligence

What changed after publication

View recent updates ↗
  1. Remediation statusRemediation status changed from Awaiting fix to Mitigation available.
    Before
    Awaiting fix
    After
    Mitigation available
    INCIBE-CERT ↗
  2. ENISA EUVD mappingEUVD-2026-81110 was added to the official ENISA EUVD mapping for this CVE.
    Before
    not recorded
    After
    {"euvdId":"EUVD-2026-81110"}
    ENISA EUVD ↗
  3. Catalogue recordCVE added to the BlackTree catalogue.
    CNA ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Remediation guidance recorded
ENISA EUVD · EUVD-2026-81110↗CVE authority or vendor reference · Cisco CISCO-SA-FMC-MULIVULNS-4PSNFWVX↗INCIBE-CERT remediation guidance↗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-2026-20341 · cve.blacktree.nl