dbcve.org
HTTP ServerWeb server / proxy · Ibm

CVE-2026-8854

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_mem_cache.

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_mem_cache module. An attacker can exploit this to cause the server to become unavailable, likely through resource exhaustion or malformed request handling in the caching module.

MitigationDisable the optional mod_mem_cache module if not required, or apply IBM's security patch when available. Monitor server availability and consider rate limiting on the caching endpoints as a temporary measure.

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. Identify IBM HTTP Server version
    Run 'httpd -v' or 'apachectl -v' from the IBM HTTP Server installation bin directory to obtain the version number
    Affected if The displayed version falls within 8.5.0.0 - 8.5.5.29 or 9.0.0.0 - 9.0.5.28
  2. Locate the IBM HTTP Server configuration file
    Find the main configuration file (typically httpd.conf or ibm_http.conf) in the conf directory of the IBM HTTP Server installation
    Affected if Configuration file exists and the server version is in the affected range
  3. Verify if mod_mem_cache module is loaded
    Search the configuration file for a LoadModule directive referencing 'mem_cache' module, or look for 'mod_mem_cache' in the loaded modules section
    Affected if A LoadModule directive for mem_cache is present and uncommented in the configuration
  4. Check for mem_cache configuration directives
    Search the configuration file for CacheEnable, MCacheSize, MCacheMaxObjectCount, or other mod_mem_cache specific directives that enable caching functionality
    Affected if CacheEnable mem_cache or other mod_mem_cache configuration directives are present and active

The environment is affected if running IBM HTTP Server version 8.5.0.0 through 8.5.5.29 or 9.0.0.0 through 9.0.5.28 with the mod_mem_cache module loaded and configured in the active 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

Disable the optional mod_mem_cache module if not required, or apply IBM's security patch when available. Monitor server availability and consider rate limiting on the caching endpoints as a temporary measure.

Recommended fix High confidence

IBM HTTP Server 8.5.5.30 or later (8.5.x branch); IBM HTTP Server 9.0.5.29 or later (9.0.x branch)

  1. 1. Identify the currently installed IBM HTTP Server version by running 'nginx -v' or checking the IBM HTTP Server documentation for your deployment method.
  2. 2. For IBM HTTP Server 8.5.x: Plan upgrade to version 8.5.5.30 or later.
  3. 3. For IBM HTTP Server 9.0.x: Plan upgrade to version 9.0.5.29 or later.
  4. 4. Download the appropriate fixed version from IBM Fix Central (https://www.ibm.com/support/fixcentral/) or your IBM entitled software repository.
  5. 5. Review IBM HTTP Server installation documentation for your platform (AIX, Linux, Windows, etc.).
  6. 6. Schedule a maintenance window and create a backup of your current IBM HTTP Server configuration.
  7. 7. Stop the IBM HTTP Server instance before applying the upgrade.
  8. 8. Install the upgraded IBM HTTP Server version following IBM's installation instructions.
Caveat Review IBM release notes for the target version for any compatibility notes or required configuration changes; minor version upgrades typically have low risk

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
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,696.

Scan for this in your stack

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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-2026-8854 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