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Remote Code Execution in IBM WebSphere Application Server JAX-WS WS-Security Deserialization

IdentifiersCVE-2026-9319CWE-502· Deserialization of Untrusted Data

CVE-2026-9319 is a potential remote code execution vulnerability affecting IBM WebSphere Application Server versions 9.0 and 8.5. The issue is caused by deserialization of untrusted data in JAX-WS messaging endpoints when WS-Security is in use. According to the provided content, attacker-controlled serialized data can be delivered to exposed JAX-WS endpoints, creating a deserialization path that may result in execution of attacker-supplied code within the WebSphere environment. The vulnerability is classified as CWE-502 and is described by IBM as network exploitable with no privileges or user interaction required, although the attack complexity is rated high.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation can result in remote code execution on the affected WebSphere Application Server instance. Given the provided CVSS characteristics and advisory text, compromise may lead to complete loss of confidentiality, integrity, and availability in the impacted security scope. In practical terms, an attacker could execute arbitrary payloads in the server context, deploy malware, manipulate application behavior or hosted services, access sensitive enterprise data processed by the application server, and disrupt service availability.

Mitigation

If you can’t patch tonight, do this now.

If immediate patching is not possible, reduce exposure by restricting network access to JAX-WS endpoints, especially those using WS-Security, to only trusted clients and internal networks. Disable or limit unnecessary JAX-WS web service endpoints where feasible, and minimize acceptance of untrusted serialized input through affected services. Additional compensating controls include segmentation, WAF or reverse-proxy filtering where applicable, strict access control to exposed SOAP services, and heightened monitoring for anomalous requests targeting WS-Security-enabled JAX-WS endpoints. The provided content does not include vendor-specified mitigations beyond patching.

Remediation

Patch, then assume compromise.

IBM has published a security advisory for CVE-2026-9319 and provided interim fixes for affected traditional WebSphere Application Server releases. The provided content indicates administrators should apply IBM's available patches/interim fixes for WebSphere Application Server 9.0 and 8.5, and specifically references APAR PH71454 as protecting local web service endpoints. Organizations should follow IBM's official guidance and upgrade or patch to the fixed maintenance level or interim fix identified in IBM advisory node 7274738.
PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType
International Business MachinesWebsphere Application Serverapplication

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

6 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.

6 SOURCESView more in app
What this page doesn’t show

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Exposure mapping

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Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity4

Community discussion across Reddit, Mastodon, and other social sources.

EXTERNAL REFERENCES
MITRE CVE
cve.org · CVE-2026-9319
NVD
nvd.nist.gov/vuln/detail/CVE-2026-9319
MITRE CWE · CWE-502
Deserialization of Untrusted Data
Vendor Advisory
ibm.com/support/pages/node/7274738
Remote Code Execution in IBM WebSphere Application Server JAX-WS WS-Security Deserialization (CVE-2026-9319) | Mallory