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HTTP ServerWeb server / proxy · Apache

CVE-2007-3847

MEDIUM · 5.0 CVSS v2.0 Published 2007-08-23
Fix available
A fix is available. Upgrade to 2.0.61 / 2.2.6 or later.
See remediation →
59/100
Remediation priority · Elevated
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
The date handling code in modules/proxy/proxy_util.c (mod_proxy) in Apache 2.3.0, when using a threaded MPM, allows remote origin servers to cause a denial of service (caching forward proxy process crash) via crafted date headers that trigger a buffer over-read.

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 · moderate confidence

Buffer over-read vulnerability in Apache mod_proxy's date handling code (modules/proxy/proxy_util.c) in version 2.3.0 when using a threaded MPM. Remote origin servers can send crafted date headers that trigger the buffer over-read, causing the caching forward proxy process to crash, resulting in denial of service.

MitigationUpgrade to a patched Apache version that addresses this vulnerability. If mod_proxy is not required, consider disabling it. Ensure threaded MPM configurations are reviewed alongside the patch deployment.

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
HTTP ServerWeb server / proxy
Affected:>= 2.0.35, < 2.0.61>= 2.2.0, < 2.2.6
FedoraOperating system
Affected:= 7
Ubuntu LinuxOperating system
Affected:= 6.06= 6.10= 7.04= 7.10
Fedora CoreOperating system
Affected:= 6

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
Authentication
None
Confidentiality
None
Integrity
None
Availability
Partial

AV:N/AC:L/Au:N/C:N/I:N/A:P

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. Check Apache version
    Run 'apache2 -v' or 'httpd -v' to determine the installed Apache version
    Affected if Version is 2.0.35 through 2.0.60, or 2.2.0 through 2.2.5 (vulnerable versions)
  2. Verify mod_proxy is loaded
    Run 'apache2 -M' or 'httpd -M' and grep for 'proxy_module', or check for 'LoadModule proxy_module' in the configuration files
    Affected if mod_proxy module is loaded and active
  3. Identify the MPM in use
    Run 'apache2 -M' or 'httpd -M' and look for 'mpm_worker' or 'mpm_event' (threaded MPMs), or check the configuration for 'Threaded' or the MPM directive
    Affected if Using a threaded MPM (worker or event) rather than prefork
  4. Confirm proxy caching or forward proxy is configured
    Search configuration files (httpd.conf, apache2.conf, included .conf files) for directives such as 'ProxyRequests On', 'ProxyPass', 'CacheEnable', or 'ProxyRemote' that enable proxy functionality
    Affected if A caching forward proxy configuration is active using mod_proxy

You are affected if you are running a vulnerable Apache version (2.0.35-2.0.60 or 2.2.0-2.2.5) with mod_proxy loaded, using a threaded MPM, and have a caching or forward proxy configuration in place.

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.

From vendor data
Upgrade available Upgrade to 2.0.61 / 2.2.6 or later
Fixed in 2.0.612.2.6
Interim mitigation

Upgrade to a patched Apache version that addresses this vulnerability. If mod_proxy is not required, consider disabling it. Ensure threaded MPM configurations are reviewed alongside the patch deployment.

Fix this in HTTP Server Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing3.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,390
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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-2007-3847 in production — separate from our analysis above.

No notes yet

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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