# CVE-2025-59340: jinjava Sandbox Bypass via JavaType-Based Deserialization

- Exploited (CISA KEV): no
- Published: 2025-09-17
- CVSS: 9.8 CRITICAL (v3.1)
- EPSS: 2.2% (82th percentile)
- CWE: CWE-1336

jinjava is a Java-based template engine based on django template syntax, adapted to render jinja templates. Priori to 2.8.1, by using mapper.getTypeFactory().constructFromCanonical(), it is possible to instruct the underlying ObjectMapper to deserialize attacker-controlled input into arbitrary classes. This enables the creation of semi-arbitrary class instances without directly invoking restricted methods or class literals. As a result, an attacker can escape the sandbox and instantiate classes such as java.net.URL, opening up the ability to access local files and URLs(e.g., file:///etc/passwd). With further chaining, this primitive can potentially lead to remote code execution (RCE). This vulnerability is fixed in 2.8.1.

## Edge WAF coverage (claimed by vendors, not measured)

| Vendor | Status | First rule | Days after publication |
|---|---|---|---|
| Cloudflare | Blocks by default | 2025-10-13 | 26 |
| AWS | No public claim | — | — |
| Microsoft Azure | No public claim | — | — |
| Google Cloud | No public claim | — | — |
| Fastly | Before feed history | — | — |
| F5 | No public claim | — | — |
| Akamai | No public source | — | — |
| OWASP CRS | No public claim | — | — |

### Cloudflare

- 2025-10-13 · new · rule b327d6442e2d4848b4aab3cbc04bab5f · default Block
  > JinJava - SSTI - CVE:CVE-2025-59340. Previous action: Log. New action: Block. This is a New Detection
  Source: https://developers.cloudflare.com/changelog/post/2025-10-13-waf-release/

"No public claim" means no vendor statement names this CVE; "Before feed history" means the CVE is older than the vendor feed. In both cases generic rules may still block it.

HTML: https://cve.vigilbase.com/cve/CVE-2025-59340 · JSON: https://cve.vigilbase.com/api/v1/cves/CVE-2025-59340