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Verint Verba CVE-2026-21730

| EUVDEUVD-2026-30284 MEDIUM
Cross-site Scripting (XSS) (CWE-79)
2026-05-14 CERT-PL GHSA-pqwf-7gjw-fvph
5.3
CVSS 4.0 · Vendor: CERT-PL
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Attack ChainAIDerived

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

  1. Access
    Access Verba login page unauthenticated
  2. Delivery
    Submit failed login with XSS payload in username
  3. Exploit
    Payload stored unsanitized in audit log
  4. Execution
    Admin opens web log viewer
  5. Persist
    Malicious script executes in admin browser session
  6. Impact
    Exfiltrate session token or perform privileged actions

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

Exploitation of the injection phase requires only network access to the Verba login page - no authentication, no special account, and no non-default configuration. The login logging feature is presumed active by default, as it is a core auditing function. However, actual payload execution is strictly conditional on an administrator opening the web-based log viewer after the malicious log entry has been written; without this admin interaction (UI:P per CVSS 4.0), the stored payload remains dormant and causes no harm. Exploitation is therefore not automatable per SSVC - the attacker cannot force or time admin access. Exploitation is also bounded to Verba versions below 10.0.6 and to environments where the web log viewer is accessible to admins (rather than log review occurring via exported files or SIEM).

Impact

The CVSS 4.0 score of 5.3 (Medium) with vector AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N accurately captures the attack profile: exploitation is trivially easy (no authentication, no complex preconditions), but actual harm is gated on an administrator passively viewing logs (UI:P). The absence of direct vulnerable-system impact (VC/VI/VA all N) reflects that Verba itself is not directly compromised - only the admin's browser session is affected. SSVC corroborates this framing: exploitation status is none, automatable is no (human interaction creates a non-automatable dependency chain), and technical impact is partial. EPSS at 0.17% (38th percentile) suggests low current exploitation interest, consistent with the absence of a public proof-of-concept and no CISA KEV listing. Despite a modest numerical score, the real-world risk in administrative environments is meaningful: a successful attack can harvest admin session tokens or perform privileged actions on behalf of the administrator, which could enable deeper compromise. The risk is not inflated by CVSS - it reflects a genuine but interaction-dependent threat.

Exploit ScenarioDerived

An unauthenticated attacker submits a failed login to the Verba web interface using a username containing a JavaScript payload designed to exfiltrate the administrator's session cookie to an attacker-controlled endpoint. The payload is written verbatim to the application's audit log. When an administrator later opens the log viewer to review failed login events, the malicious script executes in the admin's browser session, silently transmitting the session token and enabling the attacker to impersonate the administrator without further interaction.

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 – Jul 23, 2026

Stored XSS in Verba's login audit logging subsystem allows unauthenticated remote attackers to inject arbitrary JavaScript by supplying a malicious username during a failed login attempt. The payload persists unsanitized in application logs and executes within an administrator's browser session when the log viewer is accessed, enabling potential session hijacking or credential theft. No active exploitation has been confirmed (absent from CISA KEV; EPSS 0.17% at 38th percentile), and a vendor-released fix is available in version 10.0.6.

RemediationAI

Upgrade Verba to version 10.0.6 or later, which addresses the missing input sanitization in the login logging mechanism. The fix was confirmed in the CVE description and corroborated by EUVD-2026-30284; details are available via the CERT-PL advisory at https://cert.pl/en/posts/2026/05/CVE-2026-21730. Note that the vendor was unresponsive during coordinated disclosure, so independent post-upgrade testing of the log viewer is advisable to confirm the fix is effective. As a compensating control prior to patching, restrict access to the web-based log viewer to the minimum number of administrators required and enforce multi-factor authentication on all admin accounts to reduce the session-hijacking impact window. A WAF rule encoding or stripping JavaScript constructs from the username parameter at the perimeter can reduce injection success without eliminating the root cause. Reducing the frequency with which administrators access the log viewer also limits exposure, though this trades visibility for risk reduction.

Affected VersionsENISA

Verba 0 <10.0.6

Affected Packages

euvd verba fix: 10.0.6

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

Verba, developed by Verint (CPE: cpe:2.3:a:verint:verba:*:*:*:*:*:*:*:*), is a call recording and workforce optimization platform. The root cause is CWE-79 (Improper Neutralization of Input During Web Page Generation - Stored XSS): the login event logging subsystem writes the attacker-controlled username field to an audit log without applying output encoding or input sanitization. Because the application's web-based log viewer later renders these log entries directly in the browser DOM, any embedded script is interpreted and executed. The impact scope crosses component boundaries - the injection occurs at the unauthenticated login endpoint, while execution occurs in the privileged administrative log viewer, which is why the CVSS 4.0 vector carries subsequent-system confidentiality and integrity impact (SC:L/SI:L) rather than direct vulnerable-system impact.

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Severity by source

Vendor (CERT-PL) PRIMARY 5.3 MEDIUM
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
vuln.today AI 6.1 MEDIUM

No privileges needed to inject payload (PR:N), but admin must view logs (UI:R); scope changes to admin browser context (S:C) enabling limited session confidentiality and integrity impact.

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

Primary rating from Vendor (CERT-PL).

CVSS VectorVendor: CERT-PL

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
None
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

2
Patch available
May 14, 2026 - 15:01 EUVD
CVE Published
May 14, 2026 - 13:52 nvd
UNKNOWN (no severity yet)

DescriptionCVE.org

Verba is affected by a Stored Cross-Site Scripting (XSS) vulnerability within its login logging mechanism. When an unauthenticated remote attacker attempts to log in using an incorrect username and password combination, the supplied username value is recorded in the application logs. Due to lack of input sanitization, an attacker can inject a malicious XSS payload into the username field. This payload will be executed in the context of the administrator’s browser when the admin accesses the web application's log viewer.

The vendor was notified early about this vulnerability, but didn't respond to our messages. This issue was fixed in version 10.0.6

Threat Intelligence Overview

EPSS Score
0.2%
Top 62% exploitable
Prevalence
Low
niche call recording and workforce optimization platform
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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