Cyber Resilience

CVE-2025-66834

Trueconf Server 5.5.2.10813

Public PoC
Published
30 December 2025
Modified
07 January 2026
Patch / advisory
View advisory
CVSS Score v3.1 7.3
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N
EPSS Score 0.0027 18th percentile
Risk Priority 53 floored blend · peak EPSS

Summary

CVE-2025-66834 is a high-severity Improper Neutralization of Formula Elements in a CSV File (CWE-1236) vulnerability in Trueconf Server. Its CVSS base score is 7.3 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique User Execution (T1204); ranked at the 18th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to SI-15 (Information Output Filtering) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

A CSV Formula Injection vulnerability in TrueConf Server v5.5.2.10813 allows a normal user to inject malicious spreadsheet formulas into exported chat logs via crafted Display Name.

CWE(s)
CWE-1236

Related Threats

MITRE ATT&CK Enterprise Techniques

T1204 User Execution Execution
An adversary may rely upon specific actions by a user in order to gain execution.
attack.mitre.org →
T1204.002 Malicious File Execution
An adversary may rely upon a user opening a malicious file in order to gain execution.
attack.mitre.org →
T1566 Phishing Initial Access
Adversaries may send phishing messages to gain access to victim systems.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2025-66824Same product: Trueconf Server
CVE-2025-66823Same product: Trueconf Server
CVE-2024-45084Shared CWE-1236
CVE-2024-47485Shared CWE-1236
CVE-2025-54752Shared CWE-1236
CVE-2026-23873Shared CWE-1236
CVE-2023-29918Shared CWE-1236
CVE-2023-23796Shared CWE-1236
CVE-2025-1421Shared CWE-1236
CVE-2026-41073Shared CWE-1236

Affected Assets

trueconf
server
5.5.2.10813

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V1.2.10

Mitigating Controls (NIST 800-53 r5) AI

SI-15 Information Output Filtering good match

Output filtering/validation directly stops unneutralized formula elements from being written into CSV files.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly require output neutralization for untrusted CSV content to block formula injection.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.29 Security testing in development and acceptance mostly match
finds

Security testing in development can detect formula injection but does not itself implement the mitigation.

A.8.25 Secure development life cycle partial match
prevents

Secure SDLC mandates input validation and output encoding that directly prevents formula injection in CSV exports.

A.8.26 Application security requirements partial match
prevents

Application security requirements include rules for safe CSV generation and handling of untrusted data.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Secure architecture principles encourage safe data export design but do not specifically address CSV formula neutralization.

A.8.28 Secure coding partial match
prevents

Secure coding standards explicitly require neutralization of special characters when writing CSV files.

References