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CVE-2026-8834 IBM CVE debrief

IBM HTTP Server 8.5 and 9.0 contain a buffer overflow vulnerability in the Administration Server component. A privileged, authenticated attacker can exploit this flaw to achieve remote code execution or cause denial of service. The vulnerability is classified as CWE-122 (Heap-based Buffer Overflow) and carries a CVSS 3.1 score of 8.0 (High severity). Affected versions include 8.5.0.0 through 8.5.5.29 and 9.0.0.0 through 9.0.5.28. IBM has released security updates to address this issue.

Vendor
IBM
Product
HTTP Server
CVSS
HIGH 8
CISA KEV
Not listed in stored evidence
Original CVE published
2026-05-26
Original CVE updated
2026-05-26
Advisory published
2026-05-26
Advisory updated
2026-05-26

Who should care

Organizations running IBM HTTP Server 8.5 or 9.0 with Administration Server enabled should prioritize patching. Security teams responsible for web infrastructure, system administrators managing IBM HTTP Server deployments, and compliance officers tracking high-severity vulnerabilities in enterprise software should address this issue. Organizations with administrative interfaces exposed beyond internal networks face elevated risk.

Technical summary

This vulnerability exists in the IBM HTTP Server Administration Server component. The buffer overflow condition (CWE-122) can be triggered by a privileged, authenticated user, potentially leading to heap memory corruption. Successful exploitation may result in arbitrary code execution within the context of the Administration Server process or system crash. The attack requires adjacent network access and valid administrative credentials, but no user interaction. The vulnerability does not affect the core HTTP server functionality for serving web content, but rather the administrative interface used for configuration management.

Defensive priority

HIGH

Recommended defensive actions

  • Apply IBM HTTP Server fix packs 8.5.5.30 or 9.0.5.29 or later as documented in the vendor security advisory
  • Restrict administrative access to the IBM HTTP Server Administration Server to trusted networks and authorized personnel only
  • Monitor Administration Server access logs for anomalous activity from privileged accounts
  • Review and validate administrative user privileges to enforce least privilege principles
  • Consider network segmentation to limit exposure of Administration Server interfaces

Evidence notes

The vulnerability affects IBM HTTP Server versions 8.5.0.0 through 8.5.5.29 and 9.0.0.0 through 9.0.5.28, based on CPE criteria from the NVD. The CVSS vector CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H indicates attack vector is adjacent network, low attack complexity, low privileges required, no user interaction, and high impact on confidentiality, integrity, and availability. The weakness is identified as CWE-122 (Heap-based Buffer Overflow).

Official resources

IBM disclosed this vulnerability on May 26, 2026, with an updated advisory published later the same day. The vulnerability was analyzed and assigned CVSS metrics by the NVD. No known exploitation in ransomware campaigns has been reported,