CVEs / CVE-2026-116606
CVE-2026-116606: Barracuda Networks Email Security Gateway (ESG) Authentication Bypass Using an Alternate Path or Channel Vulnerability
- Known exploited in the CISA KEV catalog since 10 Nov 2026
- critical 9.3 CVSS 4.0 (from the CNA)
- EPSS 8.93% chance of exploitation in the next 30 days, higher than 95% of CVEs (11 Nov 2026)
- Last changed at its sources
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Summary
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.
Description
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.
Affected and fixed versions
| Product | Affected | Fixed in |
|---|---|---|
| Barracuda Networks Barracuda Email Security Gateway (ESG) | before 9.4.0.030 | 9.4.0.030 |
Exploitation
| In CISA KEV since | 10 Nov 2026 |
|---|---|
| Due date for US federal agencies | 13 Nov 2026 |
| Used in ransomware campaigns | Unknown |
| Required action | Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines. |
Severity
| CVSS 4.0 | 9.3 criticalCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:XScored by the CNA ([email protected]) |
|---|---|
| Weakness | CWE-288 |
On the Stackurity blog
References
- CVE-2026-116606 on NVD
- CVE-2026-116606 in the CISA KEV catalog
- https://trust.barracuda.com/security/pre-authentication-authorization-bypass-command-injection (cited by CISA)
- https://github.com/mandiant/Vulnerability-Disclosures/blob/master/2026/MNDT-2026-0042.md (cited by CISA)
- https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk (cited by CISA)
- https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk (cited by CISA)
- https://github.com/mandiant/Vulnerability-Disclosures/blob/master/2026/MNDT-2026-0042.md
- https://trust.barracuda.com/security/pre-authentication-authorization-bypass-command-injection
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-116606
Sources
Exploitation status from the CISA Known Exploited Vulnerabilities catalog. EPSS scores from FIRST. Descriptions, severity and references from the National Vulnerability Database. Open-source package versions from OSV (CC-BY 4.0). Text is shown as each source states it; Stackurity does not edit it. Check the vendor's advisory before acting.
This product uses data from the NVD API but is not endorsed or certified by the NVD.