Medium severity · published Sep 14, 2026
CVE-2026-15634
IBM WebSphere Application Server and IBM WebSphere Application Server - Liberty Request Smuggling
6.5
CVSS
0.4%
EPSS
No
On KEV
Description
IBM WebSphere Application Server 8.5 and 9.0, and IBM WebSphere Application Server - Liberty 17.0.0.3 through 26.0.0.8 are vulnerable to HTTP request smuggling, caused by improper parsing of the HTTP transfer-encoding request header. By sending a specially crafted HTTP transfer-encoding request header, an attacker could exploit this vulnerability to poison the web cache, bypass web application firewall protection, and conduct XSS attacks.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
Low
Integrity
Low
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 30% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
WA
WebSphere Application Server · IBM
9.0; 8.5 · source: vendor
WA
WebSphere Application Server - Liberty · IBM
17.0.0.3 through 26.0.0.5 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-15634
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-15634
www.ibm.com
https://www.ibm.com/support/pages/node/7286610
www.ibm.com
https://www.ibm.com/support/pages/node/7286611
More from WebSphere Application Server
9.8
CVE-2015-7450
IBM WebSphere Application Server and Server Hypervisor Edition Code Injection.
9.8
CVE-2026-8400
Multiple Vulnerabilities in IBM® Java SDK affect IBM WebSphere Application Server and WebSphere Application Server Liberty due to the July 2026 CPU
9.8
CVE-2026-14529
IBM WebSphere Application Server and WebSphere Application Server Liberty are affected by a server-side request forgery
9.8
CVE-2026-14446
IBM WebSphere Application Server is affected by a privilege escalation
9.8
CVE-2026-14512
IBM WebSphere Application Server is affected by an unsafe deserialization and exposure of sensitive information