CVE-2026-31049
Published: 14 April 2026
Summary
CVE-2026-31049 is a critical-severity Improper Neutralization of Formula Elements in a CSV File (CWE-1236) vulnerability in Hostbillapp (inferred from references). Its CVSS base score is 9.8 (Critical).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 42.2% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-2 (Flaw Remediation).
Threat & Defense at a Glance
Threat & Defense Details
Mitigating Controls (NIST 800-53 r5)AI
Directly addresses the missing server-side validation of CSV registration fields to prevent arbitrary code execution from malicious inputs.
Ensures timely patching of the specific flaw in Hostbill CSV handling as detailed in vendor advisories and release notes.
Restricts the insertion of unauthorized or malformed CSV content into registration processes to block exploitation vectors.
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Unauthenticated remote exploitation of a public-facing web application's CSV registration field enables arbitrary code execution (T1190) and privilege escalation (T1068).
NVD Description
An issue in Hostbill v.2025-11-24 and 2025-12-01 allows a remote attacker to execute arbitrary code and escalate privileges via the CSV registration field
Deeper analysisAI
CVE-2026-31049 is a critical vulnerability (CVSS 9.8, CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H) affecting Hostbill versions 2025-11-24 and 2025-12-01. The issue, classified under CWE-1236, enables a remote attacker to execute arbitrary code and escalate privileges via the CSV registration field. Published on 2026-04-14, it represents a severe flaw in the application's handling of CSV imports during registration processes.
Any remote attacker with network access can exploit this vulnerability due to its low attack complexity, lack of required privileges or user interaction, and unchanged impact scope. Exploitation through the CSV registration field allows achievement of high impacts on confidentiality, integrity, and availability, culminating in arbitrary code execution and privilege escalation on the affected Hostbill instance.
Vendor-provided resources detail potential mitigations, including a security advisory at https://blog.hostbillapp.com/2025/12/03/hostbill-security-advisory/, changelog at https://hostbillapp.com/changelog, and release notes for versions 11-27-2025 and 12-01-2025 at https://hostbillapp.com/release-notes/11-27-2025.html and https://hostbillapp.com/release-notes/12-01-2025.html. A GitHub repository at https://github.com/Muhammad5235/HostBill-CVEs-2025/blob/main/Missing%20Server-Side%20Validation/Registration%20fields%20%26%20Import%20Csv documents the missing server-side validation underlying the flaw.
Details
- CWE(s)