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HCL MyCloud EUVDEUVD-2026-46346

| CVE-2026-56583 LOW
Insufficient Session Expiration (CWE-613)
2026-07-21 HCL GHSA-m9wm-8hw7-wg6x
3.1
CVSS 3.1 · Vendor: HCL
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Attack ChainAIDerived

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

  1. Access
    Acquire valid session token via phishing or interception
  2. Exploit
    Authenticate to HCL MyCloud with stolen token
  3. Execution
    Platform permits concurrent session without invalidating prior token
  4. Impact
    Access victim account data alongside legitimate active user

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A07:2025 - Authentication Failures
ASVS 5.0
V7 - Session Management Session expiration enforcement
Exploitation Conditions

The attacker must possess a valid, authenticated session token for the target HCL MyCloud account (PR:L per CVSS), acquired through a separate attack vector such as credential phishing, token theft from an unencrypted channel, or session fixation. The platform must be running without single-session enforcement - the default vulnerable configuration described in the CVE. High attack complexity (AC:H) reflects the out-of-band prerequisite of obtaining the token itself. Exploitation is bounded strictly to confidentiality (C:L); no write or destructive actions are enabled through this vector alone. Deployments with enforced single-session policies, short session TTLs, or IP-pinned session validation would prevent exploitation of this specific weakness.

Impact

The CVSS vector AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N produces a Low score of 3.1, which accurately reflects the constrained threat model. High attack complexity (AC:H) signals that exploitation depends on conditions beyond the attacker's direct control - specifically, obtaining a valid session token through a separate attack such as phishing or network interception. Low privileges required (PR:L) confirms the attacker must already be authenticated or in possession of a legitimate credential. The impact ceiling is partial confidentiality (C:L) with zero integrity or availability consequence. No EPSS probability data was provided, KEV status is absent indicating no confirmed active exploitation, and no public proof-of-concept is known. The Authentication Bypass tag slightly elevates concern relative to the raw score, but the overall real-world risk remains low. This is a design-level session management weakness rather than an immediately weaponizable remote code execution class issue; organizations with strong credential hygiene and session monitoring controls face minimal residual risk.

Exploit ScenarioDerived

An attacker who obtains a valid authenticated session token - through phishing, credential stuffing, or network interception - presents that token to HCL MyCloud and establishes a concurrent session alongside the legitimate account owner. Because the platform does not invalidate the older token upon the new login, both sessions remain active simultaneously, allowing the attacker to browse or exfiltrate accessible cloud data without triggering reauthentication or session conflict. No public exploit code is known at time of analysis, and AC:H reflects the prerequisite difficulty of token acquisition.

Monitor Track and reassess. Why: LOW severity (CVSS 0.1-3.9).
No patch listed yet 0.1% exploitation probability (EPSS)

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AnalysisAIv1 – Jul 21, 2026

Concurrent Login Vulnerability in HCL MyCloud permits authenticated users to sustain multiple simultaneous active sessions without invalidation, enabling session hijacking and unauthorized account access. The CVSS score of 3.1 (Low) reflects high attack complexity, a prerequisite of authenticated access, and impact confined to partial confidentiality - no integrity or availability impact applies. No public exploit code and no confirmed active exploitation (CISA KEV) have been identified at time of analysis.

RemediationAI

Consult the HCL vendor advisory at https://support.hcl-software.com/csm?id=kb_article&sysparm_article=KB0132381 for official patch guidance and exact fixed version numbers, as no specific patched release is confirmed from the available intelligence data. As compensating controls pending patch deployment, administrators should enforce single active session policies that invalidate all prior sessions upon a new successful login event, preventing parallel token abuse. Session timeout windows should be shortened to reduce the viable lifetime of any intercepted token. Enabling concurrent session anomaly detection - such as alerting on simultaneous logins from geographically disparate IPs - can surface active abuse. Enforcing multi-factor authentication increases the difficulty of leveraging stolen credentials or tokens to maintain unauthorized concurrent sessions. Note that aggressive session expiration policies may degrade the experience for legitimate users operating across multiple devices simultaneously.

Affected VersionsENISA

MyCloud 10.8.2

Affected Packages

euvd mycloud 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

HCL MyCloud (cpe:2.3:a:hclsoftware:mycloud:*:*:*:*:*:*:*:*) is an enterprise cloud collaboration and file-sharing platform from HCL Software. The root cause is CWE-613 (Insufficient Session Expiration), which covers failures to properly invalidate session tokens when new login events occur or when sessions should otherwise expire. In this case, the platform fails to enforce single-session constraints or to terminate older sessions upon concurrent authentication, allowing valid session tokens to persist beyond their intended scope. This design gap means a stolen or intercepted token remains exploitable even while the legitimate user is concurrently authenticated, expanding the window of unauthorized access.

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Severity by source

Vendor (HCL) PRIMARY 3.1 LOW
AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N
vuln.today AI 3.1 LOW

Network-reachable but requires a pre-obtained valid session token (PR:L, AC:H); impact is confined to limited confidentiality disclosure with no integrity or availability consequence.

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

Primary rating from Vendor (HCL).

CVSS VectorVendor: HCL

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

DescriptionCVE.org

HCL MyCloud was affected with Concurrent Login Vulnerability. It may increase the risk of unauthorized access, session hijacking, and account misuse.

Threat Intelligence Overview

EPSS Score
0.1%
Top 96% exploitable
Prevalence
Low
niche HCL enterprise cloud product, limited public deployment footprint
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 LOW
CISA KEV No
Public POC No
EPSS 0.1%
Patch available No
Active threat No
Deciding rule
LOW severity (CVSS 0.1-3.9)
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· derived
None
System Exposure· derived
Open
Automatable· derived
No
Human Impact· derived
Low

Priority Score

16
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +16
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.

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