What is CVE-2026-8646?
IBM WebSphere Application Server 9.0 and 8.5 and IBM WebSphere Application Server - Liberty 17.0.0.3 through 26.0.0.6 are vulnerable to HTTP request smuggling. A remote attacker could smuggle a specially crafted request to the application server thereby allowing the attacker to bypass security controls, spoof identity, escalate privilege, and expose sensitive information.
The record classifies CVE-2026-8646 under weakness class CWE-444. 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. 2 affected-product entries are recorded, across 1 vendor, listed below. The identifier was first published 105 days ago.
Severity and exploitation probability
- CVSS v3.1 base score
- 7.4 — HIGH
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N - EPSS (FIRST)
- 0.3% probability of exploitation in the next 30 days, higher than 27.0% of all scored CVEs
- CISA KEV
- Not listed in the CISA Known Exploited Vulnerabilities catalog
- Threadlinqs priority
- 4.8/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- Published
- 2026-06-22
Is CVE-2026-8646 being exploited?
It currently carries a trending score of 37 in the Threadlinqs vulnerability feed.
Affected products and versions
- IBM: WebSphere Application Server, WebSphere Application Server - Liberty
How to fix CVE-2026-8646
No vendor patch reference has been recorded for CVE-2026-8646 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-2026-8646
No threat campaign in the Threadlinqs corpus currently references CVE-2026-8646, in its CVE list or as an indicator. The linkage is recomputed from the live corpus on every daily ingest, so this section fills in as soon as a tracked campaign cites the identifier.
Sources
Enriched from CVE.org, FIRST EPSS, GitHub Security Advisories. Last verified by Threadlinqs on .