Security Digest · Vulnerability record
CVE-2026-25526: JinJava Bypass through ForTag leads to Arbitrary Java Execution
JinJava is a Java-based template engine based on django template syntax, adapted to render jinja templates.
CVSS 9.8 Critical EPSS 1.0% · p63
Should you act?
Critical and remotely reachable
No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- 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 1.0%, percentile 63: FIRST’s model estimates a 1.0% chance of exploitation activity in the next 30 days, higher than 63% of all scored CVEs (moderate). 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, < 2.8.3, fixed in 2.8.3;com.hubspot.jinjava:jinjava(Maven) < 2.7.6, fixed in 2.7.6. 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. Prior to versions 2.7.6 and 2.8.3, JinJava is vulnerable to arbitrary Java execution via bypass through ForTag. This allows arbitrary Java class instantiation and file access bypassing built-in sandbox restrictions. This issue has been patched in versions 2.7.6 and 2.8.3.
From the GitHub advisory
Impact
Vulnerability Type: Sandbox Bypass / Remote Code Execution
Affected Component: Jinjava
Affected Users: - Organizations using HubSpot's Jinjava template rendering engine for user-provided template content - Any system that renders untrusted Jinja templates using HubSpot's Jinjava implementation - Users with the ability to create or edit custom code templates
Severity: Critical - allows arbitrary Java class instantiation and file access bypassing built-in sandbox restrictions
Weakness type: CWE-1336.
Product: com.hubspot.jinjava:jinjava (Maven) · Assigned by: GitHub_M · Published: 2026-02-04
Affected and fixed versions
| Ecosystem | Package | Vulnerable | First fixed |
|---|---|---|---|
| Maven | com.hubspot.jinjava:jinjava | >= 2.8.0, < 2.8.3 | 2.8.3 |
| Maven | com.hubspot.jinjava:jinjava | < 2.7.6 | 2.7.6 |
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| HubSpot | jinjava | < 2.7.6, < 2.8.3 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_M | 3.1 | 9.8 Critical | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| GitHub | 3.1 | 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Privileges required: none (no login)
- User interaction: none
- Scope: unchanged
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- 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): 1.00% probability of exploitation activity in the next 30 days; percentile 63.
Timeline
- — GitHub-reviewed advisory GHSA-gjx9-j8f8-7j74 published (critical)
- — CVE record published by GitHub_M
- — CVE record last updated
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vulnerability records
- GitHub Advisory GHSA-gjx9-j8f8-7j74 github.com
- CVE.org record CVE-2026-25526 cve.org
- NVD entry CVE-2026-25526 nvd.nist.gov
Other references from the CVE record and advisory
- github.com github.com
- github.com github.com
- github.com github.com
- github.com github.com
- github.com github.com