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WebSphere Application Server EUVDEUVD-2026-83276

| CVE-2026-11538 MEDIUM
Improper Output Neutralization for Logs (CWE-117)
2026-09-18 ibm GHSA-wgpc-w629-m235
5.3
CVSS 3.1 · NVD
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Reach WebSphere over network (unauthenticated)
  2. Exploit
    Send request with crafted LTPA token cookie
  3. Execution
    Malicious characters written unsanitized to logs
  4. Impact
    Forged/split log entries corrupt log integrity

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A09:2025 - Security Logging & Alerting Failures
ASVS 5.0
V16 - Security Logging and Error Handling Log output neutralization
Exploitation Conditions

Exploitation requires that the target WebSphere Application Server (9.0 or 8.5) processes LTPA token authentication and writes token/cookie content to its logs - the attacker supplies a crafted LTPA token cookie over the network without authentication (PR:N). The impact is limited to log integrity (forged/injected log entries); there is no confidentiality or availability impact and no code execution. Realistic risk is further limited by AC:H - the attacker needs to craft content that survives into logs in an exploitable form, and the damage only materializes when those logs are consumed by a human or downstream system that misinterprets the injected entries.

Impact

This is a genuinely low-priority issue despite being network-reachable and unauthenticated. The CVSS 3.1 base score of 3.7 (AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N) correctly reflects that the only impact is a Low integrity effect (I:L) - no confidentiality or availability loss - consistent with CWE-117 (Improper Output Neutralization for Logs), i.e. log injection, not code execution. The AC:H reflects that reliably forging useful log content and having it viewed/parsed downstream is not trivial. No EPSS score, no CISA KEV listing, and no public exploit code were provided, so exploitation status is: no public exploit identified at time of analysis. There are no conflicting signals here: all sources agree this is a low-severity log-tampering weakness, not a high-CVSS-but-hidden-risk case. The main caveat is that the input Tags label this 'Code Injection', which overstates the impact - this is log injection (CWE-117), which cannot on its own yield code execution. A patch is available from IBM (support node 7286610).

Exploit ScenarioDerived

A remote, unauthenticated attacker sends HTTP requests to a WebSphere endpoint with a crafted LTPA token cookie containing embedded control characters (e.g. CRLF or fake log-line markers). When WebSphere writes the cookie/token value to its logs without neutralization, the attacker forges or splits log entries - potentially hiding activity or planting misleading records for anyone (or any SIEM) reading the logs. No public exploit code is identified, and the CVSS AC:H indicates non-trivial conditions for reliable, impactful injection.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
Patch available 0.2% exploitation probability (EPSS)

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AnalysisAIv1 – Sep 18, 2026

Log injection in IBM WebSphere Application Server 9.0 and 8.5 lets remote, unauthenticated attackers corrupt server log content by supplying a crafted LTPA token cookie that the application writes to its logs without neutralizing control characters. The impact is limited to integrity (CVSS 3.1 base score 3.7, I:L) with no confidentiality or availability loss and no code execution, and exploitation is rated high complexity because the injected content must survive into the log in a form a human or downstream log consumer then misinterprets. No public exploit code and no confirmed active exploitation (CISA KEV) were identified at time of analysis; a vendor patch is available per the IBM advisory.

RemediationAI

Patch available per vendor advisory: IBM has published a fix for this issue and the authoritative version mapping and installation instructions are in the advisory at https://www.ibm.com/support/pages/node/7286610 - apply the interim fix or fix pack that corresponds to your installed WebSphere Application Server 8.5 or 9.0 build, since no single exact fix version is specified in the available data. If immediate patching is not possible, compensating controls should focus on removing the injection's downstream value rather than on the token itself: escape or strip CR/LF and non-printable characters from WebSphere log streams before they reach a SIEM or log-management platform (trade-off: aggressive filtering can mangle legitimate multi-line stack traces and reduce troubleshooting fidelity), and treat WebSphere application logs as untrusted input - do not use them as sole evidence for security alerts, audits, or automated remediation triggers until the fix is applied. Where SSO is not required for a given deployment, disabling or avoiding LTPA-based single sign-on for untrusted-facing endpoints removes the injection vector entirely, but this breaks cross-application SSO and forces users to re-authenticate per application. Shortening LTPA token lifetimes and rotating LTPA keys limits the window in which a captured or crafted token is usable, though it does not by itself prevent log injection; because the vector is PR:N/AV:N with no authentication, network segmentation and front-end filtering of cookie headers offer only marginal benefit and should not be relied on in place of the vendor fix.

Affected VersionsENISA

WebSphere Application Server 8.5
WebSphere Application Server 9.0

Affected Packages

euvd websphere_application_server no fix

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

The issue is an improper output neutralization flaw in logs (CWE-117) affecting IBM WebSphere Application Server, whose affected-product fingerprint is the wildcard CPE cpe:2.3:a:ibm:websphere_application_server:*:*:*:*:*:*:*:*, i.e. it spans both the 9.0 and 8.5 release trains. LTPA (Lightweight Third-Party Authentication) is IBM's single-sign-on token mechanism, typically carried in the LtpaToken/LtpaToken2 cookie, which holds a signed/encrypted representation of user identity; WebSphere can log token or cookie content during authentication and tracing. Because that content is written to log files without escaping non-printable characters, an attacker who can supply a cookie value can inject newline or control sequences and forge additional log lines. The CVSS vector CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N confirms this is network-reachable without authentication (PR:N) and requires no user interaction, but is constrained to a low integrity impact with high attack complexity (AC:H) - the payload must be crafted so it is preserved into the log and then acted upon by whatever reads it. Note that the coarse "Code Injection" tag attached to this record overstates the weakness: the root cause is log forging via unescaped input, not executable code injection, and there is no scope change or privilege escalation path in the assessed vector.

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Severity by source

Vendor (ibm) PRIMARY LOW
NVD 5.3 MEDIUM
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
vuln.today AI 3.7 LOW

Crafted cookie is sent remotely and unauthenticated (AV:N/PR:N); reliable, impactful log forgery is non-trivial (AC:H); only log integrity is affected (I:L, C:N/A:N).

3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
4.0 AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N

Primary rating from Vendor (ibm).

CVSS VectorNVD

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
None

Lifecycle Timeline

3
Severity Changed
Sep 24, 2026 - 16:07 NVD
LOW MEDIUM
CVSS changed
Sep 24, 2026 - 16:07 NVD
3.7 (LOW) 5.3 (MEDIUM)
CVE Published
Sep 18, 2026 - 19:00 nvd
LOW 3.7

DescriptionNVD

IBM WebSphere Application Server 9.0 and 8.5 is affected by a log injection vulnerability through crafted LTPA token cookies.

Threat Intelligence Overview

EPSS Score
0.2%
Top 94% exploitable
Prevalence
High
widely-deployed enterprise Java application server in large organizations
Data Quality
5 sources
Confidence: Medium

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC No
EPSS 0.2%
Patch available Yes
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Defer
Exploitation
None
System Exposure· derived
Open
Automatable
No
Human Impact· derived
Low
Technical Impact
Partial

Priority Score

26
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +26
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Code Injection CRITICAL

Code injection occurs when an application accepts user input and passes it directly into a language interpreter or evaluator without proper sanitization.

CVE-2019-4279 CRITICAL POC
9.8 May 17

IBM WebSphere Application Server 8.5 and 9.0 could allow a remote attacker to execute arbitrary code on the system with

CVE-2015-1920 CRITICAL
10.0 May 20

IBM WebSphere Application Server (WAS) 6.1 through 6.1.0.47, 7.0 before 7.0.0.39, 8.0 before 8.0.0.11, and 8.5 before 8.

CVE-2013-1777 CRITICAL
10.0 Jul 11

The JMX Remoting functionality in Apache Geronimo 3.x before 3.0.1, as used in IBM WebSphere Application Server (WAS) Co

CVE-2012-5955 CRITICAL
10.0 Dec 20

Unspecified vulnerability in the IBM HTTP Server component 5.3 in IBM WebSphere Application Server (WAS) for z/OS allows

CVE-2018-1770 MEDIUM POC
6.5 Oct 12

IBM WebSphere Application Server 7.0, 8.0, 8.5, and 9.0 could allow a remote attacker to traverse directories on the sys

CVE-2016-5983 HIGH
7.5 Oct 05

IBM WebSphere Application Server (WAS) 7.0 before 7.0.0.43, 8.0 before 8.0.0.13, 8.5 before 8.5.5.11, 9.0 before 9.0.0.2

CVE-2013-0462 CRITICAL
10.0 Jan 27

Unspecified vulnerability in IBM WebSphere Application Server (WAS) 6.1, 7.0 before 7.0.0.27, 8.0, and 8.5 has unknown i

CVE-2026-14512 CRITICAL
9.8 Jul 28

Pre-authentication unsafe deserialization in IBM WebSphere Application Server 9.0 and 8.5 traditional allows remote unau

CVE-2026-8400 CRITICAL
9.8 Aug 05

Unsafe class loading in the ORB (Object Request Broker) component of IBM WebSphere Application Server 8.5, 9.0, and Libe

CVE-2026-14974 CRITICAL
9.8 Jul 28

Remote code execution in IBM WebSphere Application Server 8.5 and 9.0 (traditional) allows an unauthenticated network at

CVE-2026-11541 CRITICAL
9.8 Jun 30

HTTP request smuggling in IBM WebSphere Application Server (traditional 8.5 and 9.0) and WebSphere Liberty (17.0.0.3 thr

CVE-2026-14529 CRITICAL
9.8 Jul 29

Server-side request forgery in IBM WebSphere Application Server (traditional 9.0 and 8.5) and WebSphere Application Serv

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