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Agora Project EUVDEUVD-2026-100579

| CVE-2026-63153 HIGH
Authorization Bypass Through User-Controlled Key (CWE-639)
2026-10-13 disclosure@vulncheck.com GHSA-pm77-x6jp-g9h6
8.6
CVSS 4.0 · Vendor: vulncheck
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Attack ChainAIDerived

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

  1. Access
    Obtain low-privileged tenant account
  2. Delivery
    Send setAffectations() request with foreign space ID
  3. Exploit
    Server inserts access record without rights check
  4. Execution
    Gain unauthorized access to restricted space
  5. Impact
    Read/alter cross-tenant data

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V8 - Authorization Object-level authorization, IDOR prevention
Exploitation Conditions

Exploitation requires (1) a reachable Agora Project instance running a version before 26.10.0, and (2) the attacker possessing a valid authenticated account on that instance (CVSS PR:L) - it is not exploitable by fully unauthenticated outsiders. The specific trigger is invoking the setAffectations() function with an attacker-chosen target space identifier; the function fails to verify that the caller holds rights over that supplied space, so the practical prerequisite is simply any login plus the ability to submit the affectation request. Limiting factors: a prior account/credential is mandatory, making this most dangerous in multi-tenant or shared-hosting deployments where untrusted users coexist; single-tenant or tightly-controlled-user instances face lower realistic risk. No special non-default configuration or user interaction is needed.

Impact

The input provides a CVSS 4.0 vector (CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N, base 8.6) describing network-reachable, low-complexity exploitation requiring low privileges (PR:L) and no user interaction - meaning any authenticated tenant user can trigger it remotely against a running instance. No EPSS score, CISA KEV entry, SSVC decision, or public POC was supplied, so there is no evidence of active or at-scale exploitation; exploitation status is 'no public exploit identified at time of analysis.' The high VC/VI (confidentiality and integrity) reflects the core harm: writing access-right records for arbitrary, caller-supplied target spaces breaks tenant isolation. The signals are internally consistent (authenticated-but-trivial authorization flaw, no availability impact), so this is a genuine priority for any multi-tenant Agora Project deployment despite the absence of exploitation telemetry - but the real-world urgency is tempered by the product's limited deployment footprint and the PR:L requirement (an attacker needs a valid account first). No conflicts exist between the CVSS vector and the description; both agree on authenticated remote access with no availability impact.

Exploit ScenarioDerived

An attacker holding any low-privileged account on a shared Agora Project instance calls setAffectations() and supplies the identifier of a space belonging to another tenant or a restricted area they have no rights to. Because the function never verifies the caller's rights over the supplied target space, the attacker inserts access-right records granting themselves (or confederates) entry, then reads or modifies the previously isolated content. No public exploit code is identified, but the flaw is a straightforward object-reference authorization bypass requiring only a crafted authenticated request.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
Patch available 0.3% exploitation probability (EPSS)

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AnalysisAIv1 – Oct 13, 2026

Authenticated users of Omnispace Agora Project instances running versions before 26.10.0 can insert access-right records (affectations) for arbitrary spaces by invoking setAffectations() with a caller-supplied target space identifier, breaking tenant isolation and extending access to spaces the caller has no rights over. Exploitation is network-reachable, low-complexity, requires only a valid account on the target instance (CVSS PR:L), and needs no user interaction or non-default configuration, yielding high confidentiality and integrity impact while availability is unaffected. No public exploit code has been identified at time of analysis, but because the flaw is a straightforward authorization-check omission reachable by any logged-in user, multi-tenant or shared-hosting deployments carry the highest realistic risk; the vendor-released fix is Agora Project 26.10.0.

RemediationAI

Upgrade to Agora Project 26.10.0 or later, which is the vendor-released patch version identified in the references (https://github.com/xech/agora-project/releases/tag/26.10); no interim vendor workaround is published. Because the fix is not called out in the 26.10.0 release notes, verify deployment by confirming the running version string rather than relying on changelog entries, and consult the vendor site at https://www.agora-project.net/ and the VulnCheck advisory at https://www.vulncheck.com/advisories/omnispace-agora-project-broken-access-control-via-setaffectations for confirmation. If immediate upgrade is not possible, the most effective compensating control is to restrict who can hold an account on the instance: disable or tightly gate self-service registration and administrative account provisioning, since a valid login is the sole prerequisite (PR:L), accepting that this does not protect multi-tenant deployments that legitimately host mutually distrusting users. As a secondary measure, audit persisted affectation records for cross-tenant entries-any affectation referencing a space the creating principal does not own-and revoke them, and enable request/application logging on the affectation-writing endpoint to detect anomalous target-space identifiers; both require database access and ongoing review effort, and neither blocks the write. Network-layer restrictions that only allow trusted tenant address ranges to reach the instance reduce exposure but degrade legitimate remote access, and generic WAF rules are unlikely to help because the malicious request is syntactically valid and differs from a legitimate one only in the target space identifier, so behavioral/authorization-aware logging is needed instead. Finally, treat the vulnerable deployment as a potential cross-tenant data exposure event: review affected spaces for unauthorized reads before patching, since the defect grants access rather than merely recording intent.

Affected VersionsENISA

Agora Project 0 <26.10.0

Affected Packages

euvd agora_project fix: 26.10.0

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 root cause is CWE-639, Authorization Bypass Through User-Controlled Key: the setAffectations() routine accepts a caller-supplied target space identifier and persists access-right records (affectations) against it without verifying that the calling principal holds any authorization over that space. In an access-control model where spaces are the tenant boundary and affectations are the mappings that grant identities visibility or rights within a space, trusting the client-proposed key effectively lets a low-privileged account write authorization data into other tenants' namespaces. This is a server-side business-logic/authorization defect in the application layer, not memory corruption or injection, so no exploit primitives beyond an ordinary authenticated HTTP request are needed. The supplied CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N) with all subsequent-system metrics (SC/SI/SA) marked N indicates the impact is confined to the vulnerable Agora instance itself, affecting confidentiality of foreign spaces and integrity of the authorization dataset, with no availability loss; our independent assessment re-scores the same behavior under CVSS 3.1 as AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N. The reporter-supplied tag "Authentication Bypass" and EUVD record EUVD-2026-100579 describe the same defect, though in CWE terms this is an authorization bypass layered on top of a legitimate authenticated session rather than a credential or authentication-mechanism bypass.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (vulncheck) PRIMARY 8.6 HIGH
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
vuln.today AI 8.1 HIGH

Authenticated user needed so PR:L; trivially scriptable request gives AC:L/AV:N; inserting access records exposes and alters restricted data (C:H/I:H) with no availability impact.

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

Primary rating from Vendor (vulncheck).

CVSS VectorVendor: vulncheck

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
Low
User Interaction
None
Vulnerable system: Confidentiality
High
Vulnerable system: Integrity
High
Vulnerable system: Availability
None
Subsequent system: Confidentiality
None
Subsequent system: Integrity
None
Subsequent system: Availability
None

Lifecycle Timeline

2
Patch available
Oct 13, 2026 - 21:05 EUVD
CVE Published
Oct 13, 2026 - 20:17 cve.org
HIGH 8.6

DescriptionCVE.org

Omnispace Agora Project before 26.10.0 contains a broken access control vulnerability in setAffectations() that allows authenticated attackers to insert access-right records for a caller-supplied target space without verifying the caller has rights to that space. Attackers can assign access affectations to spaces outside their own reach, breaking tenant isolation and granting unauthorized access to restricted spaces.

Executive ViewAI

Why It Matters

Omnispace Agora Project deployments earlier than 26.10.0 contain an authorization flaw that allows any authenticated user to grant themselves access to spaces belonging to other tenants, undermining the tenant isolation the platform is sold on. Because exploitation requires only a valid low-privileged account and no special configuration, every multi-tenant or shared-hosting customer environment is exposed to cross-tenant data disclosure and tampering until upgraded. Leadership should treat this as a customer-trust and contractual-obligation issue, not merely a technical defect, given the high confidentiality and integrity impact across hosted tenants.

Business Impact: High
Compensating Controls

Apply vendor patch.

Threat Intelligence Overview

EPSS Score
0.3%
Top 79% exploitable
Prevalence
Low
niche open-source PHP groupware, limited enterprise deployment footprint
Data Quality
6 sources
Confidence: High

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 HIGH
CISA KEV No
Public POC No
EPSS 0.3%
Patch available Yes
Active threat No
Deciding rule
HIGH severity (CVSS 7.0-8.9)
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
Scheduled
Exploitation
None
System Exposure· derived
Open
Automatable
No
Human Impact
High
Technical Impact
Partial

Priority Score

43
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +43
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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