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Agora Project EUVDEUVD-2026-100475

| CVE-2026-63157 MEDIUM
Cross-site Scripting (XSS) (CWE-79)
2026-10-13 disclosure@vulncheck.com GHSA-ghgw-7245-fm88
5.1
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
    Authenticate with low-privilege account
  2. Exploit
    Submit crafted link address via Links module
  3. Execution
    Victim opens shared links list
  4. Impact
    Script executes, hijack session

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A05:2025 - Injection
ASVS 5.0
V1 - Encoding and Sanitization Output encoding, context-aware escaping
MITRE ATT&CK

2 techniques across 2 tactics: Initial Access, Execution

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

Exploitation Conditions

Requires an authenticated account (PR:L) with access to the Links module in Agora Project before 26.10.0; the attacker stores a link whose 'adress' (link address) field carries a payload that uses unescaped quotes to escape the onclick event-handler attribute, because the application echoes that field into the handler without neutralizing quotes. The payload only executes when another user passively views the links list (UI:P - no click needed beyond opening the list), and impact is limited to that victim's browser context (client-side session hijacking), not the server. Limiting factors: attacker must already be a logged-in user, exploitation is confined to instances running a vulnerable pre-26.10.0 version, and a victim must actually load the links list.

Impact

This is a medium-severity stored XSS (CVSS 4.0 base 5.1, CWE-79) whose real-world risk is moderate and bounded, not urgent. The CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:L/UI:P) shows network reach and low complexity, but two meaningful brakes apply: the attacker needs an authenticated low-privilege account (PR:L) and a victim must passively view the links list (UI:P) for the payload to fire. Impact is confined to the victim's browser session - the vector sets direct VC:N/VI:N/VA:N and only SC:L/SI:L (low subsequent-system confidentiality/integrity), consistent with session hijacking rather than direct server compromise. No EPSS score was provided, the CVE is not on CISA KEV, and no public exploit code was supplied, so exploitation status is 'no public exploit identified at time of analysis.' There are no conflicting signals here - the CVSS, CWE, and description all agree this is an authenticated, interaction-dependent client-side flaw. The main uncertainty is deployment footprint: Agora Project is a niche open-source collaboration platform, which lowers practical priority despite network exposure. A vendor patch (26.10.0) is available, making remediation straightforward.

Exploit ScenarioDerived

An authenticated user of an Agora Project instance before 26.10.0 opens the Links module and saves a new link whose address (adress) field contains a payload that uses quotes to break out of the onclick attribute and inject script. When any other user - including an administrator - later browses the shared links list, the stored script executes in their browser, letting the attacker steal the session cookie or perform actions as that victim. No public proof-of-concept was provided in the source data, so weaponization effort is unverified.

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 – Oct 14, 2026

Stored cross-site scripting in Omnispace Agora Project versions before 26.10.0 allows an authenticated user with access to the Links module to persist a malicious 'adress' (link address) value that escapes an onclick event-handler attribute, executing script in the browser of any user who later opens the links list and enabling client-side session hijacking. The issue is medium severity (CVSS 4.0 base 5.1; independent assessment vector CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N), with the impact confined to a victim's browser context rather than the server, and it requires an already-authenticated attacker plus a victim who actually loads the links listing. Exploitation is bounded: no public exploit code and no confirmed active exploitation were identified at time of analysis, and a fixed version 26.10.0 has been released.

RemediationAI

Vendor-released patch: upgrade to Agora Project 26.10.0, published at https://github.com/xech/agora-project/releases/tag/26.10 and referenced from the vendor site https://www.agora-project.net/; the release notes for 26.10.0 document the new 2FA option, recipient sorting and large-backup optimization, so the XSS fix should be treated as included in that build even though the notes do not call it out explicitly. If upgrade cannot be performed immediately, apply output-encoding at the point where the 'adress' field is written into the onclick attribute (HTML-attribute-encode at minimum the single and double quote characters, and ideally replace the inline onclick with a data-attribute plus an external listener) - this is a code-level workaround with the trade-off that it must be re-applied after every subsequent upstream update; alternatively, restrict Links module rights to a small set of trusted accounts (only partially effective, since a trusted account can still attack others) or temporarily disable the Links module (removes the exposed feature for all users). Reviewing and purging existing stored link records for embedded quote or script characters is recommended after remediation, and monitoring accounts with Links-module access limits who can re-introduce a payload while the fix is pending. No vendor advisory beyond the release page and the VulnCheck/NVD references above was provided, and no configuration flag that disables inline event handlers was identified in the input data.

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-79 (Improper Neutralization of Input During Web Page Generation, i.e. cross-site scripting) in the stored/persistent variant. Agora Project's Links module takes user-supplied input in an 'adress' field and echoes it directly into an onclick HTML event-handler attribute without neutralizing quotation marks, so an attacker-supplied quote character terminates the attribute value and lets arbitrary JavaScript be appended to the handler. Because the payload is persisted in the application's data store, it fires for every subsequent viewer of the links list rather than only for the submitter, which is why the CVSS 3.1 assessment marks scope as changed (S:C) while availability and server-side confidentiality are unaffected (C:N/I:N/A:N at the vulnerable component, with C:L/I:L only at the subsequent browser context). EUVD lists affected range as "Agora Project 0 <26.10.0"; no CPE identifiers were supplied, and the affected technology is the PHP/MySQL-style self-hosted project-management web application distributed via the vendor site https://www.agora-project.net/ and the GitHub repository https://github.com/xech/agora-project.

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Severity by source

Vendor (vulncheck) PRIMARY 5.1 MEDIUM
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
vuln.today AI 5.4 MEDIUM

Authenticated contributor stores the payload so PR:L; a victim must view the links list (UI:R); stored XSS crosses into the victim's browser context (S:C) with low C/I and no availability impact.

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

Primary rating from Vendor (vulncheck).

CVSS VectorVendor: vulncheck

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

Lifecycle Timeline

1
Patch available
Oct 13, 2026 - 21:20 EUVD

DescriptionCVE.org

Omnispace Agora Project before 26.10.0 contains a stored cross-site scripting vulnerability that allows authenticated users to inject malicious scripts by submitting an unsanitized link address (adress) field that is echoed into an onclick event-handler attribute without neutralizing quotes. Attackers can store a crafted payload through the Links module that executes in the browser of any user viewing the links list, enabling session hijacking or further client-side compromise.

Threat Intelligence Overview

EPSS Score
0.2%
Top 88% exploitable
Prevalence
Low
niche open-source collaboration platform, limited enterprise 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 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
Scheduled
Exploitation
None
System Exposure· derived
Open
Automatable
No
Human Impact· derived
Medium
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

Cross-Site Scripting occurs when an application accepts untrusted data and sends it to a web browser without proper validation or encoding.

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