Ubuntu LinuxOperating system · Canonical
CVE-2015-8899
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 · uneditedDnsmasq before 2.76 allows remote servers to cause a denial of service (crash) via a reply with an empty DNS address that has an (1) A or (2) AAAA record defined locally.
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 confidenceDnsmasq before version 2.76 contains a vulnerability where processing a DNS reply containing an empty DNS address (with a locally-defined A or AAAA record) triggers a crash. A malicious remote DNS server can exploit this to cause a denial of service.
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
Ubuntu LinuxOperating system
= 15.10= 16.04<= 2.75CVSS 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
- None
- Integrity
- None
- Availability
- High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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 checksWork through these to decide whether this CVE applies to you.
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Identify Dnsmasq versionRun `dnsmasq --version` or `dpkg -l | grep dnsmasq` (Debian/Ubuntu) or `rpm -qa | grep dnsmasq` (RHEL/CentOS) to determine the installed version.Affected if The version number returned is lower than 2.76 (for example, 2.75, 2.74, or earlier).
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Confirm Dnsmasq is running as DNS serverRun `ps aux | grep dnsmasq` and check for DNS-related arguments such as `--local-service`, `--no-resolv`, or review the configuration file typically located at `/etc/dnsmasq.conf` or `/etc/dnsmasq.d/` for DNS server settings.Affected if Dnsmasq is running and configured to handle DNS queries (not only DHCP relay).
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Check for locally-defined A or AAAA recordsSearch configuration files for `local=/` directives or `address=/` directives that define A records (e.g., `address=/example.com/127.0.0.1`) or AAAA records (e.g., `address=/example.com/::1`).Affected if Local address records (A or AAAA) are defined in the Dnsmasq configuration.
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Verify DNS recursion is enabledInspect the configuration for absence of `recurse=no` or confirm `server=` directives point to upstream DNS servers, allowing recursive queries.Affected if Dnsmasq is configured to perform recursive DNS resolution using upstream servers.
You are affected if Dnsmasq version is below 2.76, it is running as a DNS server with recursion enabled, and the configuration contains locally-defined A or AAAA records that could be matched by a malicious upstream DNS response.
Generated from the published advisory. Verify against your own configuration.
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.
From vendor dataUpgrade Dnsmasq to version 2.76 or later. If immediate patching is not feasible, restrict DNS recursion to trusted upstream servers only.
Fix this in Ubuntu Linux
Scoped from the published advisory
- Consultation3.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,304.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2015-8899 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2015-8899 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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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.
- 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
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