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VulnerabilityPublished Updated

CVE-2026-15634: IBM WebSphere Application Server · HTTP Request/Response Smuggling

Affects IBM WebSphere Application ServerSource CVE Database V5

0

Not known to be exploited · CVSS 6.5 Medium.

Data as of 26 Oct 2026, 14:18 UTC

CVSS 3.1 base score
6.5Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.3% chance of exploitation in 30 days – higher than 30% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 14 Sep 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Affected software

ProductAffectedFixed in
IBMWebSphere Application ServerAffected
  • =9.0
  • =8.5
Fixed in–
IBMWebSphere Application Server - LibertyAffected
  • >=17.0.0.3 <=26.0.0.5
Fixed in–

CPE configurations (6)

  • cpe:2.3:a:ibm:websphere_application_server:9.0:*:*:*:*:*:*:*
  • cpe:2.3:a:ibm:websphere_application_server:9.0.0:*:*:*:*:*:*:*
  • cpe:2.3:a:ibm:websphere_application_server:8.5:*:*:*:*:*:*:*
  • cpe:2.3:a:ibm:websphere_application_server:8.5.0:*:*:*:*:*:*:*
  • cpe:2.3:a:ibm:websphere_application_server_liberty:17.0.0.3:*:*:*:*:*:*:*
  • cpe:2.3:a:ibm:websphere_application_server_liberty:26.0.0.8:*:*:*:*:*:*:*

AI-suggested

Until a fix is available, consider applying any recommended workarounds from IBM and monitor for updates.

Description

IBM WebSphere Application Server versions 8.5, 9.0, and Liberty 17.0.0.3 through 26.0.0.5 are affected by an HTTP request smuggling vulnerability due to improper parsing of the HTTP transfer-encoding header. This flaw allows attackers to craft malicious HTTP requests that can poison web caches, bypass web application firewalls, and enable cross-site scripting (XSS) attacks. The vulnerability has a medium severity rating with a CVSS score of 6.5.

References

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