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CoturnApplication · Coturn Project

CVE-2026-43915

MEDIUM · 5.4 CVSS v3.1 Published 2026-06-18
Fix available
A fix is available. Upgrade to 4.11.0 or later.
See remediation →
58/100
Remediation priority · Elevated
Remotely reachable

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Coturn is a free open source implementation of TURN and STUN Server. Versions prior to 4.11.0 contain a stored cross-site scripting (XSS) vulnerability in the web-admin HTTPS interface. An attacker who can create a TURN allocation with a crafted USERNAME value can inject HTML/JavaScript that executes when an authenticated web-admin user views the TURN session list. In configurations using anonymous TURN access (--no-auth), this may be exploitable without TURN credentials. In authenticated deployments, exploitation requires valid TURN credentials or control over a provisioned username. This issue has been fixed in version 4.11.0.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Coturn versions before 4.11.0 contain a stored XSS vulnerability in the web-admin HTTPS interface. Attackers can inject malicious HTML/JavaScript through the USERNAME field when creating a TURN allocation, which executes when an authenticated administrator views the TURN session list.

MitigationUpgrade Coturn to version 4.11.0 or later. Until upgraded, disable anonymous TURN access (--no-auth) and limit who can create TURN allocations to reduce exploitability.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
CoturnApplication
Affected:< 4.11.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify Coturn version
    Run 'turnadmin -V' or 'turnserver -V' to display the version, or check the package manager (e.g., 'dpkg -l coturn' or 'rpm -qi coturn')
    Affected if The displayed version is lower than 4.11.0 (e.g., 4.10.0, 4.9.0, etc.)
  2. Verify web-admin HTTPS interface is enabled
    Inspect the turnserver configuration file (typically /etc/turnserver.conf) for the 'secure' directive or '--secure' flag, and check that a TLS certificate is configured
    Affected if The web-admin HTTPS interface is enabled and accessible (vulnerability requires this interface to be present)
  3. Confirm TURN allocation creation is permitted
    Review the turnserver configuration for authentication settings. Check for '--no-auth' or 'no-auth' which allows anonymous access, or verify that a realm is configured that permits user-based allocations
    Affected if The server allows creation of TURN allocations with arbitrary usernames (the XSS is injected through the USERNAME field during allocation creation)
  4. Inspect existing TURN sessions for suspicious content
    Access the web-admin HTTPS interface and view the TURN session list. Examine the USERNAME fields displayed in the session list for unexpected HTML tags, script tags, or javascript: URLs
    Affected if The session list displays any USERNAME values containing HTML/JavaScript code that executes in the browser

You are affected if your Coturn version is below 4.11.0 AND the web-admin HTTPS interface is enabled AND users can create TURN allocations with arbitrary usernames.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 4.11.0 or later
Fixed in 4.11.0
Interim mitigation

Upgrade Coturn to version 4.11.0 or later. Until upgraded, disable anonymous TURN access (--no-auth) and limit who can create TURN allocations to reduce exploitability.

Recommended fix High confidence

4.11.0

  1. Download and install Coturn version 4.11.0 or later from the official repository
  2. If using a package manager, update to the latest available package containing version 4.11.0
  3. Restart the Coturn service after upgrading
  4. Verify the upgrade was successful by checking the version number

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Coturn Scoped from the published advisory
  • Consultation4.0 h
  • Implementation2.0 h
  • Testing4.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,120
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,392.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-43915 in production — separate from our analysis above.

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What this is

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What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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