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WebSphere Liberty EUVDEUVD-2026-32487

| CVE-2026-5516 MEDIUM
Race Condition (CWE-362)
2026-05-27 psirt@us.ibm.com GHSA-gccj-9cv3-fp5p
5.9
CVSS 3.1 · NVD
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Attack ChainAIDerived

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

  1. Access
    Obtain high-privilege Liberty credentials
  2. Delivery
    Authenticate to Liberty server remotely
  3. Exploit
    Initiate security-sensitive operation
  4. Execution
    Time concurrent request to hit race window
  5. Persist
    Bypass access control enforcement
  6. Impact
    Exfiltrate restricted confidential data

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A06:2025 - Insecure Design
ASVS 5.0
V15 - Secure Coding and Architecture Concurrency control, locking
MITRE ATT&CK

1 technique across 1 tactic: Privilege Escalation

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Exploitation Conditions

Exploitation requires the attacker to hold a high-privilege authenticated session on the IBM WebSphere Liberty server (CVSS PR:H), ruling out unauthenticated or low-privileged exploitation. The attack must be conducted over the network (AV:N) but requires precise timing coordination (AC:H) to hit the vulnerable window - this is not a fire-and-forget exploit. No user interaction is required once the attacker is authenticated (UI:N). The specific Liberty feature, endpoint, or configuration that introduces the vulnerable timing window is not disclosed in available data - the IBM advisory at https://www.ibm.com/support/pages/node/7273425 should be consulted for configuration-specific guidance. Exploitation is limited to confidentiality impact (I:N, A:N), meaning integrity and availability of the server are not at risk. Versions outside the range 22.0.0.11-26.0.0.5 are not listed as affected.

Impact

The overall real-world risk is moderate-to-low despite the C:H confidentiality impact. Several CVSS components heavily constrain exploitability: AC:H requires precise timing coordination, which is difficult to achieve reliably in remote network scenarios; PR:H confirms the attacker must already hold high-level authenticated access to the Liberty instance before exploitation is possible. EPSS data was not provided in the source intelligence - exploitation probability cannot be quantified. No CISA KEV listing exists, and no public POC has been identified, meaning opportunistic or commodity threat actors are unlikely to operationalize this at scale. The practical threat profile is a privileged insider or a compromised high-privilege account attempting to escalate or access data they should not reach. The CVSS score of 4.4 (Medium) is broadly consistent with these constraints. One signal worth noting: the tag 'Authentication Bypass' combined with PR:H is unusual - a high-privilege user bypassing further security controls suggests possible privilege separation or authorization policy enforcement failure rather than an authentication mechanism bypass in the traditional sense. Defenders should treat this as a targeted, low-automation threat.

Exploit ScenarioDerived

A remote attacker who has already obtained high-privileged credentials to a Liberty instance (e.g., via credential theft or insider access) initiates a sequence of operations timed to exploit a race condition in the server's security enforcement path. During the brief window when the security check and the resource access are not atomically synchronized, the attacker's request is processed with bypassed access controls, allowing them to read sensitive application data or configuration they would otherwise be denied. No public POC exists at time of analysis, meaning reliable exploitation requires custom tooling and precise timing, limiting this primarily to skilled, targeted adversaries.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
No patch listed yet 0.0% exploitation probability (EPSS)

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AnalysisAIv1 – May 27, 2026

Security bypass via race condition in IBM WebSphere Application Server Liberty 22.0.0.11 through 26.0.0.5 allows a remote, highly-privileged attacker to circumvent access controls during a narrow timing window, resulting in high-confidentiality-impact data exposure. The CVSS vector confirms network-based exploitation requiring high privileges and high attack complexity, constraining real-world risk significantly. No public exploit code and no CISA KEV listing have been identified at time of analysis.

RemediationAI

The primary remediation is to apply the IBM-issued fix referenced in the vendor advisory at https://www.ibm.com/support/pages/node/7273425. An exact patched version number was not independently confirmed from the available input data - consult the IBM support page directly for the specific fix pack or interim fix designation. As a compensating control while patching is scheduled, restrict high-privilege Liberty account access to the minimum set of trusted administrators, since PR:H means exploitation requires a high-privilege session - reducing the number of accounts with that privilege level directly narrows the attack surface. Additionally, network-layer controls that limit which hosts can authenticate to the Liberty administrative interface reduce exposure for AC:H network-vector attacks. Monitoring for anomalous authentication events or unexpected data access by privileged accounts can serve as a detective control. No side effects of the vendor patch are known from available data.

Affected VersionsENISA

WebSphere Application Server - Liberty 22.0.0.11 ≤26.0.0.5

Affected Packages

euvd websphere_application_server_liberty 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

IBM WebSphere Application Server Liberty is a lightweight Java EE/Jakarta EE application server. The vulnerability is a classic time-of-check/time-of-use (TOCTOU) or race-condition class of flaw - the description explicitly references 'a specific timing window' during which a security enforcement mechanism can be bypassed. No CWE has been formally assigned, but the behavior aligns with CWE-362 (Concurrent Execution Using Shared Resource with Improper Synchronization) or CWE-367 (TOCTOU Race Condition). The affected CPE range covers Liberty versions from 22.0.0.11 up to and including 26.0.0.5, a roughly four-year release span. The S:U (unchanged scope) CVSS component indicates the impact is confined to the Liberty application server process itself rather than escaping to the underlying OS or adjacent systems.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 5.9 MEDIUM
AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

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

Lifecycle Timeline

1
CVSS changed
Oct 26, 2026 - 11:22 NVD
4.4 (MEDIUM) 5.9 (MEDIUM)

DescriptionNVD

IBM WebSphere Application Server - Liberty 22.0.0.11 through 26.0.0.5 IBM WebSphere Application Server Liberty could allow a remote attacker to bypass security under limited conditions by exploiting a specific timing window.

Threat Intelligence Overview

EPSS Score
0.0%
Top 89% exploitable
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 0.0%
Patch available No
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
Scheduled
Exploitation
None
System Exposure· derived
Open
Automatable
No
Human Impact· derived
Medium
Technical Impact
Partial

Priority Score

30
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +30
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.

Race conditions occur when multiple concurrent requests exploit the brief time gap between checking a condition and acting upon it (TOCTOU - Time of Check, Time of Use).

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