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NVD / CVE Program· CNA GitHub_M

CVE-2026-27944: Nginx UI: Unauthenticated Backup Download with Encryption Key Disclosure

CriticalCVSS 9.8 · v3.1—Proof of concept Fix available

Noroxi assessment

Priority: Plan (action score 46/100)

  • A ready-made attack module is public (Nuclei); exploiting it takes no special expertise.
  • Public proof-of-concept code exists (GitHub); there is no record of exploitation in the wild.
  • Probability of exploitation in the next 30 days: 22.8% (FIRST EPSS); higher than 97.7% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: 0xJacky nginx-ui 2.3.3.

Add it to your regular patch cycle. Upgrade to 0xJacky nginx-ui 2.3.3 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

Nginx UI is a web user interface for the Nginx web server. Prior to version 2.3.3, the /api/backup endpoint is accessible without authentication and discloses the encryption keys required to decrypt the backup in the X-Backup-Security response header. This allows an unauthenticated attacker to download a full system backup containing sensitive data (user credentials, session tokens, SSL private keys, Nginx configurations) and decrypt it immediately. This issue has been patched in version 2.3.3.

Published
Mar 5, 2026
Updated
Jun 17, 2026
EPSS
22.8% · 97th percentile

Report tools

JSON

Action score

46

Plan

Add it to your regular patch cycle.

CVSS
39 / 40 · 9.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
7 / 30 · 22.8%

CISA SSVC decision

Exploitation
proof of concept
Automatable
yes
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · GitHub_M
9.8
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • Proof of concept exists, no weaponized module
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-27944

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
nginxuinginx ui

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • 0xJacky nginx-ui

    • < 2.3.3affected

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • nginxui nginx uibefore 2.3.3

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Gogithub.com/0xJacky/Nginx-UIfrom 0—
Gogithub.com/0xJacky/Nginx-UIbefore 2.3.32.3.3

Same product

nginxui: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-33032Nginx UI: Unauthenticated MCP Endpoint Allows Remote Nginx Takeover
    50Plan
  • CVE-2024-49368Unchecked logrotate settings lead to arbitrary command execution
    43Plan
  • CVE-2026-44015Nginx UI: Server-Side Request Forgery (SSRF) via Cluster Proxy Middleware Allows Access to Internal Services
    39Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2024-49366Oct 21, 2024 · Nginx UI's json field can construct a directory traversal payload, causing arbitrary files to be written
    30Monitor
  • ← EarlierCVE-2024-49367Oct 21, 2024 · Nginx UI's log path can be controlled
    22Monitor
  • Later →CVE-2026-33027Mar 30, 2026 · Nginx UI: Improper Path Validation Allows Recursive Deletion of the Nginx Configuration Directory
    27Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
0xJacky nginx-ui2.3.3 · descriptionVendor (CNA)
Go:github.com/0xJacky/Nginx-UI2.3.3Package registry (OSV)

Exploit status

Proof of concept available

A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.

Evidence

  • Nuclei detection template ×1
  • Proof-of-concept repository on GitHub ×7

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Proof-of-concept repository on GitHub7 repositories2026-03-10 → 2026-10-03
Nuclei detection templateNuclei template CVE-2026-27944 —

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Published
  2. First PoC+4 d
  3. TodayNov 13, 2026+253 d
EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-3303225 days apartNginx UI: Unauthenticated MCP Endpoint Allows Remote Nginx Takeover
    50Plan
  • CVE-2026-4222160 days apartnginx-ui: Unauthenticated First-Run Installer Allows Remote Initial Admin Claim
    39Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

  • CVE-2026-3303025 days apartNginx UI: Unencrypted Storage of DNS API Tokens and ACME Private Keys
    39Monitor
  • CVE-2026-4401568 days apartNginx UI: Server-Side Request Forgery (SSRF) via Cluster Proxy Middleware Allows Access to Internal Services
    39Monitor
  • CVE-2026-3302825 days apartNginx UI: Race Condition Leads to Persistent Data Corruption and Service Collapse
    28Monitor
  • CVE-2026-3302725 days apartNginx UI: Improper Path Validation Allows Recursive Deletion of the Nginx Configuration Directory
    27Monitor

Not on record for this CVE: patch commit or PR link · researcher credit · public bounty program.

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-306 · Missing Authentication for Critical Function

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

nvd-secondary

Root cause

A function added for development or support ships to production without authentication. It often relies on the assumption that it is “only reachable from the internal network.”

The bug in code

The whole CWE-306 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

ts
// Added for the support teamapp.post("/maintenance/reset", resetDevice);

Fixed

ts
if (config.maintenanceEnabled) {  app.post(    "/maintenance/reset",    requireSession, requireRole("admin"), resetDevice  );}

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

All records