CVE-2026-25529

Status: AnalyzedHigh (8.1)—

Postal is an open source SMTP server. Postal versions less than 3.3.5 had a HTML injection vulnerability that allowed unescaped data to be included in the admin interface. The primary way for unescaped data to be added is via the API's "send/raw" method. This could allow arbitrary HTML to be injected in to the page which may modify the page in a misleading way or allow for unauthorised javascript to be executed. Fixed in 3.3.5 and higher.

CVSS

Version: 3.1
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Base score: 8.1

Exploitation probability (EPSS)

Probability of exploitation in the next 30 days: 0.40%
Percentile among all scored CVEs: 32
Score date: 10/5/2026

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

🎯 ATT&CK techniques

How this vulnerability is exploited and what the attacker gains, in MITRE ATT&CK terms.

ExploitationT1190 Exploit Public-Facing Applicationinitial access75 %
Primary impactT1059.007 JavaScriptexecution80 %
Secondary impactT1565.002 Transmitted Data Manipulationimpact70 %

Acceso remoto en red sin privilegios iniciales (AV:N, PR:L se requiere para la API). HTML injection (CWE-79) en interfaz admin permite inyectar JavaScript arbitrario (XSS) o modificar contenido. Impactos: ejecución de código JavaScript en navegador (T1059.007) y manipulación de datos en la interfaz

Inferred by our analysis agent from the official description, CVSS vector and CWE, and checked by a supervisor. May contain errors.

🛡️ ATT&CK mitigations that cover these techniques

Vulnerability Scanning Restrict Web-Based Content Privileged Account Management Network Segmentation Limit Access to Resource Over Network Filter Network Traffic

Affected technologies (1)

Postalserver — Postal

CWEs

CWE-79

References

https://github.com/postalserver/postal/security/advisories/GHSA-5f4r-5jpr-rfhc

Raw JSON (NVD)

Show

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  "lastModified": "2026-06-17T10:24:47.993",
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