SubversionApplication · Apache
CVE-2016-8734
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 · uneditedApache Subversion's mod_dontdothat module and HTTP clients 1.4.0 through 1.8.16, and 1.9.0 through 1.9.4 are vulnerable to a denial-of-service attack caused by exponential XML entity expansion. The attack can cause the targeted process to consume an excessive amount of CPU resources or memory.
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 confidenceApache Subversion versions 1.4.0-1.8.16 and 1.9.0-1.9.4 are vulnerable to exponential XML entity expansion attacks via the mod_dontdothat module and HTTP clients. Attackers can send malicious XML with recursively expanding entities that cause excessive CPU and memory consumption, leading to 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
SubversionApplication
= 1.4.0= 1.4.1= 1.4.2= 1.4.3= 1.4.4= 1.4.5= 1.4.6= 1.5.0= 1.5.1= 1.5.2= 1.5.3= 1.5.4
Debian LinuxOperating system
= 8.0= 9.0CVSS 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
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.0/AV:N/AC:L/PR:L/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 installed Subversion versionRun command 'svn --version' or 'svnadmin --version' to retrieve the installed Subversion version numberAffected if Version is 1.4.0 through 1.8.16, or 1.9.0 through 1.9.4 (compare your version to this range)
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Check if Apache is serving Subversion over HTTPExamine Apache configuration files for <Location> blocks containing 'mod_dav_svn' directives, indicating HTTP/HTTPS access to Subversion repositoriesAffected if Subversion repositories are configured to be served over HTTP or HTTPS protocol
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Verify mod_dontdothat module statusCheck Apache configuration for loaded mod_dontdothat module (run 'a2query -m dontdothat' on Debian or grep for 'dontdothat_module' in httpd.conf)Affected if mod_dontdothat module is loaded in Apache and handling Subversion HTTP requests
If the installed Subversion version falls within 1.4.0-1.8.16 or 1.9.0-1.9.4 AND repositories are accessible via HTTP/HTTPS with mod_dontdothat enabled, the environment is vulnerable to this XML entity expansion DoS flaw.
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 Subversion to version 1.8.17 or later, or 1.9.5 or later to obtain the patched release that addresses this vulnerability.
Fix this in Subversion
Scoped from the published advisory
- Consultation1.0 h
- Implementation2.0 h
- Testing1.0 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 $1,424.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2016-8734 — 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-2016-8734 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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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
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