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The following technical analysis dissects CVE-2026-5516, a security vulnerability affecting IBM WebSphere Application Server Liberty. This flaw permits a remote attacker, under specific and limited conditions, to circumvent security measures by exploiting a timing window within the application’s request-handling logic. The vulnerability is classified as a security feature bypass, originating from a condition where the application may output excessive data during a precise moment of the request cycle. By carefully timing a request, a privileged attacker could potentially intercept or infer sensitive information that should otherwise be protected. The issue is present in versions 22.0.0.11 through 26.0.0.5, and the attack vector is remote, requiring authentication and high attack complexity as per its CVSS metrics. Although no public exploits have been documented, the vulnerability underscores the importance of robust session management and race condition protections. Successful exploitation could lead to the disclosure of sensitive data, but it does not directly compromise system integrity or availability. The vulnerability was officially published in May 2026 and subsequently acknowledged by IBM with the release of version 26.0.0.6, which addresses the timing-related weakness.
DailyCVE Form:
Platform: IBM WebSphere Liberty
Version: 22.0.0.11-26.0.0.5
Vulnerability: Security bypass timing
Severity: Medium
date: 2026-05-18
Prediction: 2026-06-02
What Undercode Say:
The following commands can be employed to determine if a running instance of IBM WebSphere Application Server Liberty is within the vulnerable version range and to assess exposure.
Check Liberty version from installed features
grep -i "com.ibm.websphere.productversion=" /opt/ibm/wlp/lib/versions/IBMProductVersion.properties
Alternatively, use the server command to print version details
/opt/ibm/wlp/bin/server version
For detailed product information on Liberty, examine the META-INF/MANIFEST.MF
find /opt/ibm/wlp -name "MANIFEST.MF" -exec grep -H "Bundle-Version" {} \;
To verify the presence of a security bypass condition, administrators can review server logs for unexpected data output or anomalous timing patterns. While a direct exploit script is not publicly available, the following conceptual code demonstrates how a remote attacker might attempt to reproduce the timing window:
This is a conceptual example for educational purposes.
import requests
import time
url = "https://target-liberty-server.com/protected-endpoint"
session = requests.Session()
session.auth = ('attacker', 'password') Requires valid low-privilege credentials
Attempt to trigger race condition by sending concurrent requests
def send_request():
return session.get(url, params={'exploit_timing': 'true'})
Fire multiple requests within short interval to exploit window
for _ in range(50):
resp = send_request()
Observe if any response returns privileged data
if "sensitive" in resp.text:
print("Potential security bypass detected")
time.sleep(0.001) Minimal delay to increase chance of race
Exploit:
Exploitation of CVE-2026-5516 relies on an authenticated, privileged attacker manipulating the precise timing of requests to the Liberty server. By sending a sequence of carefully orchestrated requests, the attacker aims to execute a race condition where the server inadvertently outputs sensitive data that would normally be restricted. The timing window likely exists within the authentication or authorization validation stages, where a momentary lapse occurs before security checks are fully enforced. Because the attack requires high complexity and existing privileges, it is considered non-trivial but still plausible in targeted scenarios.
Protection:
To mitigate CVE-2026-5516, IBM recommends upgrading to WebSphere Application Server Liberty version 26.0.0.6 or later. If immediate patching is not feasible, apply the interim fix PH70798 to address the bypass condition. Additionally, administrators should review access controls for high-privilege accounts and monitor for unusual request patterns.
Impact:
Successful exploitation of CVE-2026-5516 can lead to the unauthorized disclosure of sensitive information to remote, authenticated users with low privileges. However, it does not impact data integrity or system availability, as reflected in its CVSS vector (AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:N/A:N). The limited conditions required for exploitation reduce the overall risk, but organizations using affected versions should prioritize patching to prevent any potential information leakage.
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Sources:
Reported By: nvd.nist.gov
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