PaperCut NG External User Lookup Code Injection Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of PaperCut NG. Authentication is required to exploit this vulnerability. The specific flaw exists within the External User Lookup functionality. The issue results from the lack of proper validation of a user-supplied string before using it to execute Java code. An attacker can leverage this vulnerability to execute code in the context of SYSTEM. Was ZDI-CAN-21013.
Conclusion & alert: CVE-2023-39469 is rated Moderate Risk (57/100): CVSS High severity, with high exploitation likelihood (EPSS 16.58%, 95th percentile). Core evidence: EPSS ranks this CVE among the most likely to be exploited in the near term. Mandatory action: High exploitation likelihood—assess exposure and prioritize 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 | 2026-03-26 | 46.39% | 16.58% | -29.81% |
| 2 | 2026-03-14 | 51.95% | 46.39% | -5.56% |
| 3 | 2026-02-14 | — | 51.95% | — |
Full EPSS history (17 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 7.2 | 3.1 | HIGH |
|
1.2 | 5.9 | [email protected] |
| 7.2 | 3.0 | HIGH |
|
1.2 | 5.9 | [email protected] |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| papercut | papercut_mf | < 22.1.1 | cpe:2.3:a:papercut:papercut_mf:*:*:*:*:*:*:*:* |
| papercut | papercut_ng | < 22.1.1 | cpe:2.3:a:papercut:papercut_ng:*:*:*:*:*:*:*:* |
| URL | Tags |
|---|---|
| https://www.papercut.com/kb/Main/SecurityBulletinJuly2023/ | Vendor Advisory Related |
| https://www.zerodayinitiative.com/advisories/ZDI-23-1285/ | Third Party Advisory |