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T-Systems TAO CVE-2026-92976

| EUVDEUVD-2026-82863 MEDIUM
Insufficient Session Expiration (CWE-613)
2026-09-18 cve-coordination@incibe.es GHSA-f95c-wf66-hq9m
5.1
CVSS 4.0 · Vendor: incibe
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Attack ChainAIDerived

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

  1. Access
    Authenticate as low-privileged user
  2. Delivery
    Inject script into profile personal-data field
  3. Exploit
    Payload stored server-side
  4. Execution
    Admin/other user views profile
  5. Persist
    Script executes in victim browser
  6. Impact
    Steal session or act as victim

Vulnerability Assessment

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

Exploitation requires an authenticated TAO 2.0 account with the ability to edit the personal-data fields of the profile management functionality (PR:L). The injected HTML/JavaScript is persistently stored and only triggers when a second party - another user or administrative staff - subsequently views the affected profile (UI:P), so it is not fully self-triggering. There are no additional non-default configuration prerequisites stated; the limiting factors are the required authentication and the dependency on a victim viewing the malicious profile. Impact is scoped to the victim's browser session (session data access and actions with the victim's permissions), not the underlying server.

Impact

This is a real but modest-priority issue. The CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:L/UI:P) confirms network-reachable, low-complexity, authenticated (PR:L) exploitation that depends on a victim passively viewing the malicious profile (UI:P). Impact is confined to the subsequent system (the victim's browser session): SC:L/SI:L with no impact to the vulnerable system itself (VC:N/VI:N/VA:N), consistent with classic stored XSS. No EPSS score, no CISA KEV listing, and no public POC are present in the provided data, so there is no public exploit identified at time of analysis and no evidence of active exploitation. The vendor score of 5.1 (Medium) is reasonable - the authentication requirement and the need for another user to view the payload limit real-world blast radius. NOTE A DATA CONFLICT: the assigned CWE-613 (Insufficient Session Expiration) does not match the description, which unambiguously describes stored Cross-Site Scripting (CWE-79) - verify the weakness classification with the coordinator (INCIBE).

Exploit ScenarioDerived

A low-privileged authenticated TAO 2.0 user edits their own profile and injects a malicious <script>/HTML payload into a personal-data field. The payload is stored and later executes in the browser of any user - including administrative staff - who views that profile, enabling session data theft or actions performed with the victim's privileges. No public exploit code is currently identified.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
No patch listed yet 0.4% exploitation probability (EPSS)

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AnalysisAIv1 – Sep 18, 2026

Stored cross-site scripting in the profile management functionality of T-Systems' TAO 2.0 suite lets an authenticated user plant malicious HTML or JavaScript inside their own personal-data fields, which is then persisted unsanitised and rendered to whoever views that profile - including administrative staff. Because the payload executes in the viewer's browser under their own session context, the attacker can read session-available information and perform actions with the victim's permissions; server-side data remains out of scope per the assessed vector (S:C with C:L/I:L only on the subsequent system). Exploitation requires a valid TAO 2.0 account with permission to edit profile fields (PR:L) plus a second party actually opening the tainted profile (UI:P), so it is a real but modest-priority issue rather than a self-propagating or unauthenticated attack, and no public exploit code or active exploitation is identified at time of analysis.

RemediationAI

No vendor-released patch or fixed version was identified at time of analysis, so remediation must start by tracking the INCIBE-CERT advisory (https://www.incibe.es/en/incibe-cert/notices/aviso/stored-cross-site-scripting-xss-t-systems-tao-20) and requesting a fixed TAO 2.0 build or hotfix from T-Systems before applying any version claimed as patched - do not assume a specific fix version exists. Until then, apply targeted compensating controls with their trade-offs in mind: enforce context-aware output encoding and HTML sanitisation on all profile personal-data fields on render (the correct long-term fix, but requires an application change or reverse-proxy/WAF response-rewriting that can break legitimate formatting in profile displays); disable or restrict rich-text/HTML entry in profile fields so only plain text is accepted (effective and low-risk, but reduces profile functionality); deploy a strict Content-Security-Policy on TAO pages that disallows inline and third-party script (mitigates execution but can break inline scripts and requires careful tuning and testing); restrict who can view profiles to those who need it and isolate administrative profile review from high-value privileged sessions (limits blast radius but adds operational friction); and harden the session layer with HttpOnly and SameSite cookies, short session timeouts, and re-authentication for sensitive administrative actions (relevant given the CWE-613 listing and the session-scoped impact, though this does not remove the injection itself). Monitor application logs for unexpected markup stored in profile fields and for anomalous requests originating from TAO profile pages to detect attempted exploitation.

Affected VersionsENISA

TAO 2.0

Affected Packages

euvd tao 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

The flaw is a persistent (stored) cross-site scripting condition in the TAO 2.0 profile management module: user-supplied values in personal-data fields are written to the application datastore without adequate output encoding or input sanitisation, then emitted verbatim into HTML when another user or administrator opens the affected profile page. The result is script execution in the victim's browser origin, which is why both the CVSS 4.0 vector (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) and the independent 3.1 assessment (AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N) score only subsequent-system confidentiality and integrity as Low and leave the vulnerable system itself unaffected. Two analytical caveats are worth flagging: the supplied CWE is CWE-613 (Insufficient Session Expiration), which does not describe the stored-XSS root cause class (CWE-79, Improper Neutralization of Input During Web Page Generation) and is likely a catalogue mismatch, and no CPE identifiers were provided, so the affected build/version range of the TAO 2.0 suite could not be pinned from the available data.

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Severity by source

Vendor (incibe) 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 user injects the payload (PR:L), a different victim must view it (UI:R), and script executing in the victim's browser crosses a security boundary (S:C) with limited confidentiality/integrity 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 (incibe).

CVSS VectorVendor: incibe

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

DescriptionCVE.org

A stored Cross-Site Scripting (XSS) vulnerability in the profile management functionality of T-Systems’ TAO 2.0 suite. An authenticated user could inject malicious HTML or JavaScript content into the fields containing their personal data. The content entered is stored and displayed without being properly sanitised when another user, including administrative staff, views the affected profile. Successful exploitation could allow JavaScript code to be executed in the victim’s browser, access to information available within the session, or the performance of actions using the victim’s permissions.

Threat Intelligence Overview

EPSS Score
0.4%
Top 69% exploitable
Prevalence
Low
T-Systems TAO 2.0 suite is a niche vendor-specific enterprise product
Data Quality
4 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 0.4%
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

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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