Review reviewCritical

CVE-2026-8856

IBM HTTP Server, http server, aix

IBM HTTP Server 8.5, and 9.0 is vulnerable to denial of service in configurations where an attacker has write access to parts of the server configuration.

CVSS
9.1
EPSS
-
- percentile
CISA KEV
Not listed
Published
2026.05.27
PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability-
Technical severityCVSS 9.1

Vulnerability overview

IBM HTTP Server 8.5, and 9.0 is vulnerable to denial of service in configurations where an attacker has write access to parts of the server configuration.

Affected product and versions

Product
IBM HTTP Server, http server, aix
Affected versions
>= 8.5.0 <= Interim Fix 002, >= 9.0, >= 8.5.0.0 < 8.5.5.30, >= 9.0.0.0 < 9.0.5.29
Fixed versions
8.5.5.30, 9.0.5.29

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
  1. 1
    Identify

    Confirm that IBM HTTP Server, http server, aix and an affected version are present.

  2. 2
    Prioritize

    Combine exploitation signals with asset exposure and business criticality.

  3. 3
    Remediate

    Follow the vendor advisory or supported update path and preserve rollback options.

  4. 4
    Verify

    Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
CWE
CWE-400