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Thelia EUVDEUVD-2026-97493

| CVE-2026-109396 LOW
Improper Neutralization of Formula Elements in a CSV File (CWE-1236)
2026-10-12 VulnCheck GHSA-w4v5-q3gm-mcf9
2.3
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
    Submit formula payload in registration/checkout/newsletter field
  2. Exploit
    CSVSerializer stores and exports value verbatim
  3. Execution
    Admin exports data and opens CSV in spreadsheet
  4. Impact
    Formula executes on admin workstation

Vulnerability Assessment

Weakness
CWE
ASVS 5.0
V1 - Encoding and Sanitization CSV injection prevention
Exploitation Conditions

Exploitation requires that an administrator export customer, order, or newsletter/mailing data via Thelia's CSV export (CSVSerializer) and then open the resulting file in a spreadsheet application (Excel, LibreOffice Calc, Google Sheets) that evaluates leading-'=','+','-','@' cells as formulas. The injection vector is unauthenticated: any visitor can supply crafted values through registration, checkout, or newsletter fields that begin with those trigger characters. Limiting factors that reduce real-world risk: the payload lies dormant until an admin performs both the export and the open action (UI:R/AT:P), modern spreadsheet applications display a warning before executing external/dynamic formulas, and impact is confined to the administrator's client workstation rather than the Thelia server. Affected only before 3.1.2 and 3.2.0 through 3.2.0 (fixed in 3.2.1).

Impact

This is a genuinely low-priority issue, and the available signals are consistent on that point. The only numeric signal provided is the vendor/VulnCheck CVSS 4.0 vector (CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P), scored 2.3 (Low). While AV:N and PR:N look alarming in isolation (a remote, unauthenticated attacker can inject the payload), the AC:H, AT:P and UI:P metrics correctly capture that code never executes on the Thelia server - it executes only if and when an administrator exports customer/order/newsletter data to CSV and opens it in a spreadsheet application that evaluates the formula. No EPSS score was provided, so exploitation probability cannot be quantified. The CVE is NOT listed in CISA KEV and no public POC is referenced, so this is no public exploit identified at time of analysis. CWE-1236 (formula injection) combined with the confirmed patch commits supports the technical description. There is no conflict between the signals: this is a low-CVSS, low-real-risk, operator-dependent weakness rather than a server-side RCE. The one nuance to verify is that impact is entirely client-side on the administrator's workstation, not on the e-commerce platform itself - raw AV:N can mislead triage tooling into over-prioritizing it.

Exploit ScenarioDerived

An unauthenticated visitor registers an account, places an order, or subscribes to the newsletter, entering a value such as '=cmd|'/C calc'!A1' or '@SUM(...)' into a name, address or phone field. Later, a store administrator exports the customer, order or mailing list to CSV and opens it in Excel or LibreOffice, at which point the spreadsheet interprets the cell as a formula and may run it, enabling data exfiltration (e.g. via auto-executed hyperlinks) or command execution on the admin's workstation. No public exploit code is referenced, and the attack depends on the admin both exporting and opening the file in a formula-evaluating application.

Monitor Track and reassess. Why: LOW severity (CVSS 0.1-3.9).
Patch available 0.2% exploitation probability (EPSS)

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AnalysisAIv1 – Oct 12, 2026

CSV formula injection in Thelia (before 3.1.2 and 3.2.0 through 3.2.0, fixed in 3.2.1) lets unauthenticated visitors plant spreadsheet formulas in registration, checkout, and newsletter fields that are later exported verbatim by CSVSerializer and executed when an administrator opens the file in Excel, LibreOffice Calc, or Google Sheets. The attacker never touches the Thelia server: impact is limited to the exporting administrator's workstation, and exploitation depends on an admin both performing the export and opening the resulting file (CVSS 3.1 AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N; CVSS 4.0 base 2.3). No public exploit code and no confirmed active exploitation have been identified at time of analysis, and the low EPSS-style risk profile is consistent with the assessed vector - this is a genuinely low-priority issue that vendor patches already resolve.

RemediationAI

Vendor-released patch: Thelia 3.1.2 (for 3.1.x and earlier) and Thelia 3.2.1 (for the 3.2 branch) - upgrade to these versions, which introduce the SpreadsheetFormulaGuard class and apply it inside CSVSerializer::serialize so exported cells are neutralized at the source. The relevant upstream changes are commits c00a26f0631ed9de3c4466176db6e808a25034aa and 6e46059225d87565caf4859ec0f764354e82ce95, with release notes at https://github.com/thelia/thelia/releases/tag/3.1.2 and https://github.com/thelia/thelia/releases/tag/3.2.1 and the advisory at https://github.com/thelia/thelia/security/advisories/GHSA-gcgv-f8rf-w2wc. Where upgrading is not immediately possible, compensate on the administrator side rather than the input side, since filtering registration/checkout/newsletter fields for leading '=', '+', '-', '@' risks breaking legitimate negative amounts and international phone numbers: import exported CSV files as data (Data > From Text/CSV, or a scripted parser) instead of double-clicking them into Excel, and keep Excel Protected View and macro/ActiveX/DDE restrictions enabled - trade-off is a slower manual workflow. LibreOffice Calc and Google Sheets can be configured to treat formula evaluation more conservatively, though this reduces normal spreadsheet functionality, and no CSV export should be opened on a workstation with access to sensitive files or network shares. Reviewing previously exported customer and newsletter CSVs created before the patch is also prudent, since any file already downloaded may still contain live formula payloads.

Affected VersionsENISA

Thelia 0 <3.1.2
Thelia 3.2.0 <3.2.1

Affected Packages

euvd thelia fix: 3.1.2, 3.2.1

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

Thelia is a PHP/Symfony-based open-source e-commerce platform. The flaw is a classic CSV/spreadsheet formula injection (CWE-1236) rooted in the export layer: core/lib/Thelia/Core/Serializer/Serializer/CSVSerializer.php wrote customer-, order-, and mailing-derived strings into CSV cells without neutralizing values whose first character is a formula trigger. Spreadsheet applications treat cells beginning with '=', '+', '-', '@' (and, in some parsers, tab or carriage return) as formulas, so attacker-controlled names, addresses, company fields, or phone numbers such as '=1+2' or '@SUM(1+1)' became live formulas on the administrator's desktop - the historical precursor to DDE-based command execution in Excel. Because the injection point is public-facing form input while the trigger is an administrative export, this is a stored, client-side injection with a two-step exploitation chain rather than a direct server compromise. The upstream fix adds Thelia\Domain\DataTransfer\Export\SpreadsheetFormulaGuard, which prefixes a leading apostrophe to any string starting with =, +, -, @, tab, or CR so the spreadsheet renders it as literal text; plain numeric values (including negatives like '-5.00' and phone numbers like '+33612345678') are deliberately left untouched via a regex guard so amounts and phone numbers are not corrupted into text. CSVSerializer::serialize calls SpreadsheetFormulaGuard::neutralize on each value, and a new integration test (SpreadsheetFormulaExportTest) asserts customer export, order export, and mailing export paths emit neutralized cells. CPE data (cpe:2.3:a:thelia:thelia:*:*:*:*:*:*:*:*) confirms the affected product family; the advisory is GHSA-gcgv-f8rf-w2wc.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Vendor (VulnCheck) PRIMARY 2.3 LOW
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
vuln.today AI 4.7 MEDIUM

Unauthenticated remote injection (AV:N/PR:N) but code runs only after an admin exports and opens the CSV in a separate spreadsheet app (AC:H/UI:R/S:C) with limited client-side impact (C:L/I:L).

3.1 AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N
4.0 AV:N/AC:H/AT:P/PR:N/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
High
Attack Requirements
Present
Privileges Required
None
User Interaction
Passive
Vulnerable system: Confidentiality
Low
Vulnerable system: Integrity
Low
Vulnerable system: Availability
None
Subsequent system: Confidentiality
None
Subsequent system: Integrity
None
Subsequent system: Availability
None

DescriptionCVE.org

Thelia before 3.1.2 and 3.2.x before 3.2.1 contains a CSV formula injection vulnerability that allows unauthenticated visitors to inject spreadsheet formulas by supplying crafted registration, checkout or newsletter fields. Attackers can submit names, addresses or phone values starting with =, +, - or @ that CSVSerializer exports verbatim, executing formulas in the administrator's spreadsheet application.

Threat Intelligence Overview

EPSS Score
0.2%
Top 92% exploitable
Prevalence
Low
niche open-source PHP e-commerce platform, limited production 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 0.2%
Patch available Yes
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

12
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +12
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Code Injection CRITICAL

Code injection occurs when an application accepts user input and passes it directly into a language interpreter or evaluator without proper sanitization.

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