CyberSecBulletin
CVE-2026-8620NVD status: Analyzed

Web Server Plug-ins for WebSphere Application…: Inconsistent Interpretation of HTTP Requests

Published Updated By the CyberSecBulletin desk

CVE-2026-8620 is a high-severity inconsistent interpretation of HTTP requests vulnerability in Web Server Plug-ins for WebSphere Application Server and WebSphere Liberty from IBM, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected Web Server Plug-ins for WebSphere Application Server and WebSphere Liberty versions: 8.5, 9.0 through Interim Fix 002. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.28% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Websphere Application Server to 8.5.5.30 or 9.0.5.28, whichever matches your release line, or a later version.
  2. Read the advisory on ibm.com for workarounds and exact fixed builds.
  3. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
IBMWeb Server Plug-ins for WebSphere Application Server and WebSphere Liberty8.5, 9.0 through Interim Fix 002Not stated
IBMWebsphere Application Server8.5.0.0 up to, but not including, 8.5.5.30; 9.0.0.0 up to, but not including, 9.0.5.288.5.5.30, 9.0.5.28

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
HighSuccess depends on conditions outside the attacker's control.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
ChangedThe attack can reach beyond the vulnerable component into other systems.
Confidentiality
HighAll data handled by the component can be read.
Integrity
LowLimited modification of data is possible.
Availability
NoneAvailability is not affected.

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:L/A:N. Scored by CNA (us.ibm.com).

Official description

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 HTTP request smuggling in the Web Server Plug-ins through a specially crafted request.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Inconsistent Interpretation of HTTP Requests

The product acts as an intermediary HTTP agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed HTTP requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination.

How developers prevent this class of flaw

  • Use a web server that employs a strict HTTP parsing procedure, such as Apache.
  • Terminate the client session after each request.

More Inconsistent Interpretation of HTTP Requests vulnerabilities (CWE-444)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in Web Server Plug-ins for WebSphere Application Server and WebSphere Liberty

All Web Server Plug-ins for WebSphere Application Server and WebSphere Liberty vulnerabilities

Recent Inconsistent Interpretation of HTTP Requests vulnerabilities

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