---
title: "CVE-2026-91403: Oracle Java SE & GraalVM - Broken Access Control"
description: "Oracle Java SE, Oracle GraalVM for JDK, and Oracle GraalVM Enterprise Edition [affected versions: Java SE 8u511, 8u511-perf, 11.0.33, 17.0.21, 21.0.13, 25.0.5, 27.0.1; GraalVM for JDK 17.0.21, 21.0.13; GraalVM Enterprise Edition 21.3.20] contain an unauthorized data access and modification vulnerability caused by insecure API handling in JSSE component, letting unauthenticated network attackers create, delete, or modify critical data, exploit requires network access without authentication."
url: https://panop.io/threat-heartbeat/CVE-2026-91403/
---

# CVE-2026-91403 Oracle Java SE & GraalVM - Broken Access Control

Oracle Java SE, Oracle GraalVM for JDK, and Oracle GraalVM Enterprise Edition \[affected versions: Java SE 8u511, 8u511-perf, 11.0.33, 17.0.21, 21.0.13, 25.0.5, 27.0.1; GraalVM for JDK 17.0.21, 21.0.13; GraalVM Enterprise Edition 21.3.20\] contain an unauthorized data access and modification vulnerability caused by insecure API handling in JSSE component, letting unauthenticated network attackers create, delete, or modify critical data, exploit requires network access without authentication.

CVSS base score 9.1 /10

Critical

CISA KEV

Not listed

Public exploit

None known

Authentication

Not required

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-91403)

## Details

Type

Broken Access Control

Impact

Data Tampering, Information Disclosure

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Published

21 October 2026

Updated

22 October 2026

## Vendor fix

Update to the latest available versions of Oracle Java SE, Oracle GraalVM for JDK, and Oracle GraalVM Enterprise Edition.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-91403](https://nvd.nist.gov/vuln/detail/CVE-2026-91403)
- [https://www.oracle.com/security-alerts/alert-cve-2026-91403.html](https://www.oracle.com/security-alerts/alert-cve-2026-91403.html)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

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