Vulnerability · Published Jul 29, 2026 · Assigned by Toreon
CVE-2026-9177Server-Side Template Injection in SecureTransport's Apache Velocity mail templates
Critical 9.4
In plain English
A critical-severity security flaw in SecureTransport from Axway. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 43% of all known vulnerabilities).
Official description
A Server-Side Template Injection (SSTI) vulnerability was identified in the mail template functionality of the Axway SecureTransport product in version 5.5-20260326. This flaw allows an attacker with admin privileges to inject arbitrary Java code expressions, which are executed server-side when the template is rendered (i.e., during email sending). Successful exploitation of this flaw allows an attacker to execute arbitrary code on the server that results in full host compromise. This issue affects all Axway SecureTransport versions prior 5.5-20260528 update.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Axway | SecureTransport | 5.5-20260326 – before 5.5-20260528 |
Weakness: CWE-1336 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
References
- https://support.axway.com/news/4882/lang/en vendor-advisory, mitigation, patch, customer-entitlement
- https://www.toreon.com/CVE-2026-9177 technical-description
- https://docs.hackjiji.org/blog/cve-2026-9177-ssti-in-securetransport-mft-gateway technical-description