---
title: "CVE-2025-59340: jinjava has Sandbox Bypass via JavaType-Based Deserialization"
url: https://erroneo.us/security/cve/CVE-2025-59340/
description: "CVE-2025-59340 (com.hubspot.jinjava:jinjava (Maven)): jinjava is a Java-based template engine based on django template syntax, adapted to render jinja…"
type: vulnerability-record
section: "Security Digest"
date_published: 2025-09-17
date_modified: 2026-07-31
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2025-59340"
kev: false
cvss: 9.8
epss: 0.02109
license: All rights reserved. Quote with attribution and a link.
---

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

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 2.1% , percentile 82: FIRST’s model estimates a 2.1% chance of exploitation activity in the next 30 days, higher than 82% of all scored CVEs (elevated). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes com.hubspot.jinjava:jinjava (Maven) = 2.8.0, fixed in 2.8.1 ; com.hubspot.jinjava:jinjava (Maven) >= 2.7.0, < 2.7.5, fixed in 2.7.5 . Check your lockfile, including transitive dependencies.

## What it is

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.

## Affected packages

- Maven `com.hubspot.jinjava:jinjava` = 2.8.0 → fixed: 2.8.1
- Maven `com.hubspot.jinjava:jinjava` >= 2.7.0, < 2.7.5 → fixed: 2.7.5

## Affected products (CVE record)

- HubSpot jinjava: < 2.8.1

## Severity

- GitHub_M CVSS 3.1: 9.8 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`
- GitHub CVSS 3.1: 9.8 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none , automatable yes , technical impact total .
- FIRST EPSS (model of 2026-10-21): 2.11% probability of exploitation activity in the next 30 days; percentile 82.

## Sources

- [GitHub Advisory GHSA-m49c-g9wr-hv6v](https://github.com/advisories/GHSA-m49c-g9wr-hv6v)
- [CVE.org record CVE-2025-59340](https://www.cve.org/CVERecord?id=CVE-2025-59340)
- [NVD entry CVE-2025-59340](https://nvd.nist.gov/vuln/detail/CVE-2025-59340)
- [github.com](https://github.com/HubSpot/jinjava/security/advisories/GHSA-m49c-g9wr-hv6v)
- [github.com](https://github.com/HubSpot/jinjava/commit/66df351e7e8ad71ca04dcacb4b65782af820b8b1)
- [github.com](https://github.com/HubSpot/jinjava/releases/tag/jinjava-2.8.1)
- [github.com](https://github.com/HubSpot/jinjava/releases/tag/jinjava-2.7.5)
- [github.com](https://github.com/github/advisory-database/pull/8141)

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Source page: https://erroneo.us/security/cve/CVE-2025-59340/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt