Vulnerability report

Exploitation Attempts Observed Confirmed Confidence Not in CISA KEV

CVE-2026-116606

Barracuda Email Security Gateway (ESG) Authentication Bypass

Barracuda Email Security Gateway (ESG · affected before 9.4.0.030

Watch CVE-2026-116606 Browse KEV feed
Severity
CVSS 9.3 · Critical
Confidence
Confirmed
Exploit status
Exploitation Attempts Observed in the Wild
EPSS
0.7%
First observed
09 Nov 2026
Last observed
09 Nov 2026

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

CVE-2026-116606 is an unauthenticated vulnerability affecting Barracuda Email Security Gateway (ESG.

Have exploitation attempts been observed?

Yes. Previdian sensors have observed 2 exploitation attempts, 1 unique attacker IP, and 1 country targeting CVE-2026-116606. First observed Nov 09, 2026. Confidence is confirmed.

Who is affected?

Barracuda Email Security Gateway (ESG affected before 9.4.0.030.

What should we do?

Patch immediately, validate internet-facing exposure, and monitor for matching requests.

Overview

Barracuda Email Security Gateway (ESG) Authentication Bypass

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.

Barracuda Networks Affected
Barracuda Email Security Gateway (ESG)
Before 9.4.0.030
View vendor advisory (opens in new tab)
Published
02 Nov 2026
Exploitation Attempts Reported
09 Nov 2026
Attack vector
Remote
Complexity
Low
Privileges
None
User interaction
None

Tags

edge

CVE References

Exploitation evidence

Evidence of exploitation attempts

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploitation Attempts Observed in the Wild

Previdian

Recorded 09 Nov 2026

Previdian sensors observed exploitation attempts targeting this vulnerability.

Exploitation Attempts Observed

Previdian sensor

First observed 09 Nov 2026

Previdian sensors observed exploitation attempts targeting this vulnerability.

Proof of concept available

GitHub

Recorded 03 Nov 2026

Public scanner or PoC coverage increases practical exploitability.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the Previdian Pro API.

Learn about Pro API access
Source Added
Previdian Sensors First 2026-11-09 09:23 UTC

Operational indicators for this CVE are listed under Detection.

Sensor telemetry

Previdian Sensor Observations

Previdian sensor observations are exploitation attempts targeting this vulnerability. They do not show that the target was vulnerable or that the attempt succeeded. The cards and chart show volume, unique attackers, and daily activity.

2

Attempts observed

1

Unique attacker IPs

1

Attacker countries

FR

2

Sensors observed

CVE-2026-116606 exploitation attempts over the last 7 days

Daily events observed by Previdian sensors

Updated 09 Nov 2026

0
0
0
0
0
0
2
3 Nov 4 Nov 5 Nov 6 Nov 7 Nov 8 Nov 9 Nov

First observed 09 Nov 2026 · Last observed 09 Nov 2026

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Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Observed signals

Request targets
User-Agents
Callback hosts
1
1
0

Request targets and User-Agents available in Pro. Callback host details available in Enterprise.

Virtual patch status

No Previdian virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.

Learn about virtual patches →

Attacker IP Indicators

Attacker IP indicators observed · available in Pro and Enterprise.

Sensor-derived attacker IP indicators are available to Pro and Enterprise accounts under Detection and through the Pro API.

Learn about Pro API access

Scanner Artifacts

Scanner and exploit-framework references linked to this CVE.

Scanner Reference Detected
Nuclei https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2026/CVE-2026-116606.yaml 09 Nov 2026

Risk and context

Severity, weaknesses, and research context

CVSS v4.0

9.3 Critical

Potential damage if exploited. Separate from whether attackers are using it.

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

EPSS

0.7%

Estimated chance of exploitation in the next 30 days. Previdian's warning comes from evidence, not this score.

Weaknesses

Authentication Bypass Using an Alternate Path or Channel CWE-288

Recent mention · Security Affairs

Security Affairs newsletter Round 603 by Pierluigi Paganini – INTERNATIONAL EDITION

A new round of the weekly Security Affairs newsletter has arrived! Every week, the best security articles from Security Affairs are free in your email box. Enjoy a new round of the weekly SecurityAffairs newsletter, including international press. Inside ARTEX: AI Hacking...

Read full advisory

All Mentions

Recent mention · Security Affairs

Security Affairs newsletter Round 603 by Pierluigi Paganini – INTERNATIONAL EDITION

Security Affairs · 08 Nov 2026

A new round of the weekly Security Affairs newsletter has arrived! Every week, the best security articles from Security Affairs are free in your email box. Enjoy a new round of the weekly SecurityAffairs newsletter, including international press. Inside ARTEX: AI Hacking Tools, Exposed Servers and South Korean Bank Breaches One Product Isn’t the Problem: […]

Recent mention · The Hacker News

Experts Demonstrate Barracuda Email Security Gateway Chain Enabling Root Access Without Login

The Hacker News · 06 Nov 2026

Swati KhandelwalNov 06, 2026Vulnerability / Email Security Two flaws in Barracuda's Email Security Gateway, an email-filtering appliance, can be chained to run commands on it as root, its highest level of access, with no login required. The company released patches on Monday, and the security firm watchTowr detailed the attack chain on Thursday. One flaw, CVE-2026-116606, is an authorization bypass. An unauthenticated attacker can use it to restore a crafted configuration backup and change the appliance's global settings. The other, CVE-2026-111560, is a command injection. It runs...

Recent mention · watchTowr

Barracuda Networks is your new best friend (Barracuda Email Security Gateway Pre-Auth Remote Root RCE CVE-2026-116606 / CVE-2026-111560)

watchTowr · 05 Nov 2026

Yes, that's right! Today we're at the aquarium.Welcome back to yet another watchTowr Labs blog post. You can begin preparing your comments now. What Is A Barracuda, And Why? Must We?Barracuda’s Email Security Gateway solution (ESG) is no stranger to love, for

Recent mention · Security Affairs

Two Barracuda ESG Flaws Could Be Combined for Full Root Access; Patches Released

Security Affairs · 04 Nov 2026

Barracuda patched two flaws that can be chained to give attackers root access to Email Security Gateway appliances. Barracuda has patched two vulnerabilities that can be chained to gain root access to its Email Security Gateway (ESG) appliances. CVE-2026-116606 (CVSS score of 9.3) is an authentication bypass that lets unauthenticated attackers modify appliance configurations. CVE-2026-111560 […]

Recent mention · NCSC Security Advisories

NCSC-2026-0465 [1.00] [M/H] Kwetsbaarheden verholpen in Barracuda Email Security Gateway

NCSC Security Advisories · 04 Nov 2026

Barracuda heeft kwetsbaarheden 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...

Recent mention · The Hacker News

Barracuda Flaws Could Be Chained to Bypass Authorization and Gain Root Access

The Hacker News · 03 Nov 2026

Ravie LakshmananNov 03, 2026Vulnerability / Network Security Barracuda has disclosed details of two vulnerabilities affecting its products that, if chained together, could allow an attacker to bypass authorization controls and gain root access to a susceptible device. The vulnerabilities, a pre-authentication authorization bypass vulnerability and a command injection vulnerability, have been assigned the CVE identifiers CVE-2026-116606 (CVSS score: 9.3) and CVE-2026-111560 (CVSS score: 8.6), respectively. While CVE-2026-116606 only affects Email Security Gateway, CVE-2026-111560 impacts...

Potential Proof of Concepts

These PoCs are unverified and could contain malware. Use at your own risk.

watchtowrlabs/watchTowr-vs-Barracuda-RCE-CVE-2026-116606-CVE-2026-111560

github · Created 2026-11-03 19:20:25 UTC · 0 stars · AI assessment 84%

Barracuda Email Security Gateway - Authentication Bypass

nuclei · Created Unknown

Timeline

From disclosure to observed exploitation attempts

  1. 04:31 UTC

    Nuclei template available

    Scanner coverage available

  2. 01:29 UTC

    Indicator of compromise added

    Indicators of compromise recorded

  3. 01:29 UTC

    Observed by Previdian sensors

    Previdian sensors observed exploitation attempts targeting this vulnerability.

  4. 19:20 UTC

    Public PoC available

    Public proof-of-concept code published

  5. 17:20 UTC

    Added to the Previdian watchlist

    Pro and Enterprise Watch users had 6 days of early warning before Previdian KEV.

  6. 12:59 UTC

    CVE published

    Vulnerability disclosed publicly

  7. 16:04 UTC

    CVE ID reserved

    Identifier reserved by the CNA

Pro API

Automate this intelligence

Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

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  • Evidence confidence and provenance
  • First-party sensor telemetry
  • PoC and scanner references
  • Affected versions and enrichment
  • Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2026-116606

Sample API response 
{
  "cve_id": "CVE-2026-116606",
  "confidence": "Confirmed",
  "cvss_score": 9.3,
  "cvss_estimated": false,
  "epss_score": 0.00728,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": true
  },
  "sensor_telemetry": { "attempts": 2, "sensors": 2 }
}