Ashlar-Vellum Cobalt XE File Parsing Integer Overflow Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of Ashlar-Vellum Cobalt. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file. The specific flaw exists within the parsing of XE files. The issue results from the lack of proper validation of user-supplied data, which can result in an integer overflow before writing to memory. An attacker can leverage this vulnerability to execute code in the context of the current process. Was ZDI-CAN-25264.
Conclusion & alert: CVE-2025-2021 is rated Moderate Risk (47.1/100): CVSS High severity, with low exploitation likelihood (EPSS 0.23%). Mandatory action: Review affected assets and schedule remediation.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2026-04-22 | 0.45% | 0.23% | -0.22% |
| 2 | 2026-04-20 | 0.38% | 0.45% | +0.07% |
| 3 | 2026-04-19 | — | 0.38% | — |
Full EPSS history (12 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 7.8 | 3.0 | HIGH |
|
1.8 | 5.9 | [email protected] |
| URL | Tags |
|---|---|
| https://www.zerodayinitiative.com/advisories/ZDI-25-125/ | Third Party Advisory |