CVE-2025-66834Public exploitNetwork attack vector

Spreadsheet code execution via unsanitized Display Name

Published Dec 30, 2025 · Updated Dec 30, 2025

CSV formula injection in TrueConf Server 5.5.2.10813 allows remote authenticated users to execute spreadsheet formulas through chat exports. The chat reporting module writes a user-controlled Display Name directly into semicolon-delimited CSV output without neutralizing formula-leading characters. Exploitation requires a normal user to join a conference and an administrator to export and open the chat log in a formula-evaluating spreadsheet, enabling code execution or data exfiltration on the administrator's system.

CVSS severity7.3
High
EPSS probability0.30%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

CSV formula injection in TrueConf Server 5.5.2.10813 allows remote authenticated users to execute spreadsheet formulas through chat exports. The chat reporting module writes a user-controlled Display Name directly into semicolon-delimited CSV output without neutralizing formula-leading characters. Exploitation requires a normal user to join a conference and an administrator to export and open the chat log in a formula-evaluating spreadsheet, enabling code execution or data exfiltration on the administrator's system.

The record

CVE
CVE-2025-66834
Published
Dec 30, 2025
Updated
Dec 30, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-1236, T1204.002
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 30, 2025CVE publishedPublication date reported by the CVE source.
  2. Dec 30, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.3CISA-ADPCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-1236Improper Neutralization of Formula Elements in a CSV File
T1204.002Malicious File

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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