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Full vulnerability report · 2026
CVE-2026-116606High confidence

Barracuda Networks Email Security Gateway (ESG) Authentication Bypass Using an Alternate Path or Channel Vulnerability

Barracuda Networks · Barracuda Email Security Gateway (ESG)

9.3CriticalCVSS 4.0
Recommended action
Protect now

CISA confirms exploitation in the wild and lists 2026-11-13 as the remediation due date.

Fix not verified
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.
  • The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
  • EPSS is 10.95% for the current model date.

Compensating controls

  • 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 Barracuda Networks Barracuda Email Security Gateway (ESG) and falls inside the recorded affected range.
  2. Recheck the vendor advisory before scheduling a change because no verified fixed version is currently retained.
  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-2026-115149

No EUVD known-exploited evidence

An authentication bypass in Barracuda Email Security Gateway versions earlier than 9.4.0.030 allows an unauthenticated remote attacker to invoke a configuration-import function and restore a crafted, compatible backup archive, resulting in unauthorized modification of the appliance’s global configuration.

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
9.3 · CVSS 4.0
Advisory evidence
No linked advisory details stored yet
Recommended actionProtect now

CISA confirms exploitation in the wild and lists 2026-11-13 as the remediation due date.

Fix not verified
01

What, why and how

Barracuda Networks Email Security Gateway (ESG) contains an authentication bypass using an alternate path or channel that could allow an unauthenticated remote attacker to invoke a configuration-import function and restore a crafted, compatible backup archive, resulting in unauthorized modification of the appliance’s global configuration. This vulnerability can be chained with CVE-2026-111560.

What

Barracuda Networks Email Security Gateway (ESG) contains an authentication bypass using an alternate path or channel that could allow an unauthenticated remote attacker to invoke a configuration-import function and restore a crafted, compatible backup archive, resulting in unauthorized modification of the appliance’s global configuration. This vulnerability can be chained with CVE-2026-111560.

Why

The product requires authentication, but the product has an alternate path or channel that does not require authentication.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may bypass an access boundary or take over an account.

What

Barracuda Networks Email Security Gateway (ESG) contains an authentication bypass using an alternate path or channel that could allow an unauthenticated remote attacker to invoke a configuration-import function and restore a crafted, compatible backup archive, resulting in unauthorized modification of the appliance’s global configuration. This vulnerability can be chained with CVE-2026-111560.

Why

The product requires authentication, but the product has an alternate path or channel that does not require authentication.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may bypass an access boundary or take over an account.

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 2026-11-10.

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 → Authentication Bypass Using an Alternate Path or Channel → bypass an access boundary or take over an account
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-288 ↗

CWE-288: Authentication Bypass Using an Alternate Path or Channel. The product requires authentication, but the product has an alternate path or channel that does not require authentication.

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:H/SC:N/SI:N/SA:N

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.VAHighVulnerable-system availability: A successful attack can cause a major 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
Stolen credentials, tokens and legitimate administration functions may provide continued access without deploying a large custom toolset.
NetworkUnauthenticatedCWE-288CISA KEV
A

Official authority intelligence

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

ENISA EUVD · EUVD-2026-115149Official EUVD mapping

An authentication bypass in Barracuda Email Security Gateway versions earlier than 9.4.0.030 allows an unauthenticated remote attacker to invoke a configuration-import function and restore a crafted, compatible backup archive, resulting in unauthorized modification of the appliance’s global configuration.

Official EUVD record ↗
BSI · German · WID-SEC-2026-4295Barracuda Networks Email Security Gateway und Web Application Firewall: Mehrere Schwachstellen

Ein entfernter, authentisierter Angreifer kann mehrere Schwachstellen in Barracuda Networks Email Security Gateway und Barracuda Networks Web Application Firewall ausnutzen, um beliebigen Programmcode mit Administratorrechten auszuführen und die Authentifizierung zu umgehen. Durch die Kombination dieser Schwachstellen kann der Angreifer Root-Zugriff auf das Gerät erlangen.

Official advisory ↗
Canadian Centre for Cyber Security · English · AV26-1112Barracuda Networks security advisory (AV26-1112) – Update 2

As of November 2, 2026, Barracuda Networks is affected by a vulnerability in the following products: Update 1

Official advisory ↗
CSIRT Italia · Italian · barracuda-disponibile-poc-per-lo-sfruttamento-delle-cve-2026-116606-e-cve-2026-111560Barracuda: disponibile PoC per lo sfruttamento delle CVE-2026-116606 e CVE-2026-111560

Disponibile Proof of Concept (PoC) per lo sfruttamento delle vulnerabilità identificate tramite le CVE-2026-116606 e CVE-2026-111560 che interessano vari prodotti Barracuda. Nel dettaglio: la CVE-2026-116606 - di tipo “ Authentication Bypass ” e con score CVSS 4.0 pari a 9.3 - interessa Barracuda Email Security Gateway (ESG) ed è dovuta ad un errore di gestione del flusso applicativo durante la procedura di cambio password amministrativa. In determinate condizioni, quando il cambio password fallisce ( ERROR_PASSWD_CHANGE ), il software segnala correttamente il problema all'utente ma non interrompe l'elaborazione della richiesta come previsto. Ne deriva che alcune operazioni successive possono essere processate nonostante si sia verificata una condizione che avrebbe dovuto bloccare immediatamente la richiesta. Un attaccante non autenticato, in grado di raggiungere l'interfaccia amministrativa del dispositivo, potrebbe sfruttare tale vulnerabilità tramite l'invio di richieste appositamente predisposte che innescano una condizione di errore nella procedura di cambio password amministrativa, inducendo il software a elaborare richieste che avrebbero dovuto essere respinte ed eludendo così i controlli di autenticazione. la CVE-2026-111560 - di tipo “ OS Command Injection ” e con score CVSS 4.0 pari a 8.6 - interessa i prodotti Barracuda Email Security Gateway (ESG), Load Balancer Application Delivery Controller (ADC), Web Application Firewall (WAF), Web Security Gateway (WSG), Message Archiver (BMA) e WAF Control Center (WCC). Questa vulnerabilità è dovuta all'inadeguata neutralizzazione di metacaratteri della shell all'interno del campo di configurazione del fuso orario ( system_timezone ). Un attaccante autenticato potrebbe sfruttare tale vulnerabilità per inserire all'interno di tale campo, un valore appositamente predisposto contenente comandi di sistema che, quando il parametro viene successivamente elaborato dal prodotto, vengono eseguiti con privilegi elevati. La concatenazione delle due vulnerabilità consente ad un attaccante remoto non autenticato, in grado di raggiungere l'interfaccia amministrativa del dispositivo, di aggirare i controlli di autenticazione e ottenere l'esecuzione di codice arbitrario con privilegi elevati sul sistema interessato.

Official advisory ↗
KISA KrCERT/CC · Korean · KNVD-7064美 CISA 발표 주요 Exploit 정보공유(Update. 2026-11-10)

Barracuda Networks Email Security Gateway (ESG) Authentication Bypass Using an Alternate Path or Channel Vulnerability Barracuda Networks Multiple Products OS Command Injection Vulnerability

Official advisory ↗
NCSC-NL · Dutch · NCSC-2026-0465Kwetsbaarheden verholpen in Barracuda Email Security Gateway

Barracuda heeft twee kwetsbaarheden vastgesteld in verschillende Barracuda-producten: een kwetsbaarheid voor het omzeilen van autorisatiecontroles (CVE-2026-116606) en een kwetsbaarheid voor command injection (CVE-2026-111560). De eerste kwetsbaarheid betreft een pre-authentication authorization bypass in Barracuda Email Security Gateway (ESG). De tweede kwetsbaarheid betreft command injection en treft naast ESG ook de Load Balancer Application Delivery Controller (ADC), Message Archiver (BMA), WAF Control Center (WCC), Web Application Firewall (WAF) en Web Security Gateway (WSG). Volgens Barracuda is voor succesvolle exploitatie toegang tot de administratieve interface van een kwetsbaar product vereist. Wanneer beide kwetsbaarheden in combinatie worden misbruikt, kan een aanvaller autorisatiecontroles omzeilen en roottoegang tot het apparaat verkrijgen. Update: Barracuda geeft in een update in de advisory aan dat er bij enkele organisaties actief misbruik van de kwetsbaarheden is waargenomen.

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 not verified
Affected
Barracuda Email Security Gateway (ESG): < 9.4.0.030
Fixed
No fixed version is explicitly recorded in the structured CVE data.
Action
No verified patch reference is present in the current structured sources. Check the vendor advisory before making a change.
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 2 Nov 2026 · Last source change 11 Nov 2026, 04:55 UTC · CWE-288 · Authentication Bypass Using an Alternate Path or Channel

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 2026-11-03
European sourceENISA EUVD · EUVD-2026-115149
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. Vendor guidanceAuthoritative vendor guidance changed: added vendor advisory: trust.barracuda.com/pre-authentication-authorization-bypass-command-injection.
    Before
    no authoritative guidance recorded
    After
    vendor advisory: trust.barracuda.com/pre-authentication-authorization-bypass-command-injection
    mandiant-cve@google.com ↗
  2. CISA KEV stateCISA KEV now confirms exploitation in the wild.
    Before
    not listed in CISA KEV
    After
    listed in CISA KEV since 2026-11-10
    CISA KEV ↗
  3. ENISA EUVD mappingEUVD-2026-115149 was added to the official ENISA EUVD mapping for this CVE.
    Before
    not recorded
    After
    {"euvdId":"EUVD-2026-115149"}
    ENISA EUVD ↗
  4. Catalogue recordCVE added to the BlackTree catalogue.
    CNA ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Added to CISA KEV
ENISA EUVD · EUVD-2026-115149↗CISA KEV record↗Vendor advisory↗CVE authority or vendor 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-2026-116606 · cve.blacktree.nl