dbcve.org
HTTP ServerWeb server / proxy · Apache

CVE-2004-0748

MEDIUM · 5.0 CVSS v2.0 Published 2004-10-20
Fix available
A fix is available. Upgrade to 2.0.51 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
mod_ssl in Apache 2.0.50 and earlier allows remote attackers to cause a denial of service (CPU consumption) by aborting an SSL connection in a way that causes an Apache child process to enter an infinite loop.

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

mod_ssl in Apache 2.0.50 and earlier contains a denial of service vulnerability where aborting an SSL connection in a specific manner causes an Apache child process to enter an infinite loop, resulting in excessive CPU consumption.

MitigationUpgrade to Apache 2.0.51 or later which contains the patched mod_ssl module, or apply the vendor-supplied patch if upgrading is not immediately feasible.

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, < 2.0.51

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. Determine Apache HTTP Server version
    Run `apachectl -v` or `httpd -v` to display the server version
    Affected if Version is 2.0.35 through 2.0.50 inclusive (2.0.35 <= version < 2.0.51)
  2. Verify mod_ssl module is loaded
    Run `apachectl -M 2>/dev/null | grep -i ssl` or inspect the configuration files for a LoadModule ssl_module directive
    Affected if mod_ssl module is loaded into Apache
  3. Confirm SSL is configured and enabled
    Check for SSL virtual host configurations in httpd.conf, ssl.conf, or included configuration files. Look for SSLEngine on directives.
    Affected if SSL virtual hosts are defined and SSLEngine is set to On
  4. Identify if the server accepts SSL connections
    Review Listen directives and virtual host configurations to determine if the server is configured to accept HTTPS requests on port 443
    Affected if The server listens on HTTPS ports and serves SSL-enabled sites

Affected if running Apache 2.0.35 through 2.0.50 with mod_ssl loaded and SSL connections enabled, as the infinite loop condition is triggered when specific SSL connection aborts occur

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 2.0.51 or later
Fixed in 2.0.51
Interim mitigation

Upgrade to Apache 2.0.51 or later which contains the patched mod_ssl module, or apply the vendor-supplied patch if upgrading is not immediately feasible.

Fix this in HTTP Server Scoped from the published advisory
  • Consultation1.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,040
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,664.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2004-0748 — 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-2004-0748 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