# CVE-2026-8633 — IBM Web Server Plug-ins for WebSphere Application Server and WebSphere Liberty

> As of 2026-05-27, CVE-2026-8633 is a CRITICAL-severity vulnerability in IBM Web Server Plug-ins for WebSphere Application Server and WebSphere Liberty, CVSS v3.1 9.8, EPSS 0.9% (59.8th percentile). Threadlinqs Intelligence links 1 tracked threat campaign to CVE-2026-8633, most recently “IBM WebSphere Application Server & Liberty Web Server Plug-ins Unauthenticated RCE and HTTP Request Smuggling (CVE-2026-8633, CVE-2026-8620)”.

**Last updated:** 2026-05-27

## What is CVE-2026-8633?

IBM Web Server Plug-ins for WebSphere Application Server and WebSphere Liberty 8.5, 9.0 IBM WebSphere Application Server and WebSphere Application Server Liberty are vulnerable to remote code execution in the Web Server Plug-ins, through a specially crafted request.

The record classifies CVE-2026-8633 under weakness class [CWE-94](https://intel.threadlinqs.com/cwe/CWE-94). Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction, and has high impact on confidentiality, integrity, availability. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 138 days ago.

## Severity and exploitation probability

- **CVSS v3.1 base score:** 9.8 — CRITICAL (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **EPSS (FIRST):** 0.9% probability of exploitation in the next 30 days, higher than 59.8% of all scored CVEs
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 7.3/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-05-26, last modified 2026-05-27

## Is CVE-2026-8633 being exploited?

It currently carries a trending score of 20 in the Threadlinqs vulnerability feed.

## Affected products and versions

- [IBM](https://intel.threadlinqs.com/vendors/ibm): Web Server Plug-ins for WebSphere Application Server and WebSphere Liberty

## How to fix CVE-2026-8633

No vendor patch reference has been recorded for CVE-2026-8633 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

## Threat activity tracking CVE-2026-8633

1 tracked threat in the Threadlinqs corpus references CVE-2026-8633, either in the campaign’s CVE list or as an indicator on the campaign record.

- [IBM WebSphere Application Server & Liberty Web Server Plug-ins Unauthenticated RCE and HTTP Request Smuggling (CVE-2026-8633, CVE-2026-8620)](https://intel.threadlinqs.com/threat/TL-2026-0650) — CRITICAL · 2026-06-01

## Sources

Enriched from CVE.org, FIRST EPSS, GitHub Security Advisories. Last verified by Threadlinqs on 2026-10-10.

**Vendor advisory and patch**

- [ibm.com — vendor advisory](https://www.ibm.com/support/pages/node/7274072)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-8633
Full detection coverage and IOCs for threats exploiting CVE-2026-8633 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp