dbcve.org
Debian LinuxOperating system · Debian

CVE-2019-25032

CRITICAL · 9.8 CVSS v3.1 Published 2021-04-27
Fix available
A fix is available. Upgrade to 1.9.5 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

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
Unbound before 1.9.5 allows an integer overflow in the regional allocator via regional_alloc. NOTE: The vendor disputes that this is a vulnerability. Although the code may be vulnerable, a running Unbound installation cannot be remotely or locally exploited

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

Unbound DNS server before version 1.9.5 contains an integer overflow vulnerability in the regional allocator function (regional_alloc). This flaw could potentially cause memory corruption when the allocator calculates memory allocation sizes. The vendor disputes the exploitability, claiming no remote or local exploitation is possible on a running Unbound installation.

MitigationUpgrade Unbound to version 1.9.5 or later to patch the integer overflow in the regional allocator. If immediate upgrade is not feasible, ensure Unbound services are not exposed to untrusted network inputs.

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
Debian LinuxOperating system
Affected:= 9.0
UnboundApplication
Affected:< 1.9.5

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
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

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. Determine if Unbound DNS server is installed
    Run 'unbound -V' or 'unbound-control status' to check for Unbound and retrieve its version number
    Affected if Unbound is installed with a version lower than 1.9.5 (for example, 1.9.4, 1.9.0, 1.6.x, etc.)
  2. Query package manager for installed Unbound version
    On Debian-based systems, run 'dpkg -l | grep unbound' or 'apt-cache policy unbound' to list the installed package version
    Affected if The installed package version is below 1.9.5
  3. Check if Unbound service is currently running
    Run 'systemctl status unbound' or 'service unbound status' to see if the Unbound service is active
    Affected if Unbound is running and the version is below 1.9.5 - note the vendor disputes that a running service is exploitable
  4. Verify if Unbound is exposed to untrusted network inputs
    Review network configuration files (such as /etc/unbound/unbound.conf) and check if control-port or remote-control interfaces are enabled and accessible from untrusted networks
    Affected if Unbound is exposed to untrusted network inputs and the version is below 1.9.5 - this increases potential attack surface despite vendor dispute

You are affected if Unbound DNS server is installed and the version is below 1.9.5, regardless of whether the vendor claims the flaw is not exploitable on a running installation.

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 1.9.5 or later
Fixed in 1.9.5
Interim mitigation

Upgrade Unbound to version 1.9.5 or later to patch the integer overflow in the regional allocator. If immediate upgrade is not feasible, ensure Unbound services are not exposed to untrusted network inputs.

Recommended fix High confidence

Unbound 1.9.5 or later

  1. Check the current version of Unbound installed (e.g., unbound -V or dpkg -l unbound)
  2. Upgrade Unbound to version 1.9.5 or later using the system's package manager (e.g., apt-get update && apt-get install unbound)
  3. Verify the upgrade was successful by checking the version again
  4. Restart the Unbound service to apply the changes (e.g., systemctl restart unbound or service unbound restart)
Caveat Review release notes for 1.9.5 to check for any configuration or behavior changes

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

Fix this in Debian Linux Scoped from the published advisory
  • Consultation2.0 h
  • Implementation1.0 h
  • Testing2.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,060
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,696.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2019-25032 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

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-2019-25032 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data