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HTTP ServerWeb server / proxy · Ibm

CVE-2026-8850

HIGH · 7.5 CVSS v3.1 Published 2026-05-26
Fix available
A fix is available. Upgrade to 8.5.5.30 / 9.0.5.29 or later.
See remediation →
84/100
Remediation priority · High
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
IBM HTTP Server 8.5, and 9.0 is vulnerable to denial of service via the optional module mod_ibm_upload.

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

IBM HTTP Server versions 8.5 and 9.0 contain a denial of service vulnerability in the optional mod_ibm_upload module. The vulnerability allows an attacker to potentially cause the server to become unavailable.

MitigationIf the mod_ibm_upload module is not required, disable or remove it from the IBM HTTP Server configuration. Monitor IBM security advisories for patches and apply them when available.

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:>= 8.5.0.0, < 8.5.5.30>= 9.0.0.0, < 9.0.5.29

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
None
Integrity
None
Availability
High

CVSS:3.1/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 checks

Work through these to decide whether this CVE applies to you.

  1. Confirm IBM HTTP Server is installed
    Run 'httpd -v' or 'apachectl -v' from the IBM HTTP Server installation bin directory to retrieve the installed version number
    Affected if The command fails or IBM HTTP Server is not present - then not affected
  2. Check if mod_ibm_upload is loaded
    Search for 'LoadModule ibm_upload_module' or 'mod_ibm_upload' in the httpd.conf configuration file and any included configuration files under the conf directory
    Affected if The module directive is present and uncommented - the module is loaded and potentially vulnerable
  3. Verify the installed version against affected ranges
    Compare the version obtained in step 1 against the affected ranges: 8.5.0.0 through 8.5.5.29, or 9.0.0.0 through 9.0.5.28
    Affected if The installed version is 8.5.0.0 through 8.5.5.29, or 9.0.0.0 through 9.0.5.28 - the version is vulnerable
  4. Confirm upload module is actively used
    Review the httpd.conf and any included files for 'Upload' directives or review any web application configurations that utilize the upload functionality provided by mod_ibm_upload
    Affected if Upload-related directives are present and the module is actively configured for handling file uploads - the attack surface is present

The environment is affected if IBM HTTP Server version is 8.5.0.0-8.5.5.29 or 9.0.0.0-9.0.5.28 AND the mod_ibm_upload module is loaded and configured in the server configuration.

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 8.5.5.30 / 9.0.5.29 or later
Fixed in 8.5.5.309.0.5.29
Interim mitigation

If the mod_ibm_upload module is not required, disable or remove it from the IBM HTTP Server configuration. Monitor IBM security advisories for patches and apply them when available.

Recommended fix High confidence

IBM HTTP Server 8.5.5.30 or later for 8.5.x line; IBM HTTP Server 9.0.5.29 or later for 9.0.x line

  1. 1. Identify the current IBM HTTP Server version by running 'apachectl -v' or checking the installation
  2. 2. If running 8.5.x version (>= 8.5.0.0, < 8.5.5.30), plan upgrade to 8.5.5.30 or later
  3. 3. If running 9.0.x version (>= 9.0.0.0, < 9.0.5.29), plan upgrade to 9.0.5.29 or later
  4. 4. Before upgrading, review IBM HTTP Server release notes for the target version for any compatibility notes
  5. 5. Stop the IBM HTTP Server instance
  6. 6. Download the appropriate fix pack from IBM Fix Central (fixcentral.ihost.com) or IBM Passport Advantage
  7. 7. Install the upgrade following IBM installation instructions for your platform
  8. 8. Verify the module mod_ibm_upload is properly configured if still needed
Caveat Review IBM release notes for potential compatibility impacts; mod_ibm_upload module functionality should be preserved but verify configuration after upgrade

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

Fix this in HTTP Server 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
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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-2026-8850 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