Oracle Java SE up to 27 Compiler improper authorization

Summaryinfo

A vulnerability marked as critical has been reported in Oracle Java SE up to 27. This affects an unknown function of the component Compiler. This manipulation causes improper authorization. This vulnerability is tracked as CVE-2026-91487. The attack is possible to be carried out remotely. No exploit exists. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in Oracle Java SE up to 27. It has been declared as critical. Affected by this vulnerability is an unknown code of the component Compiler. The manipulation with an unknown input leads to a improper authorization vulnerability. The CWE definition for the vulnerability is CWE-285. The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

Vulnerability in Oracle Java SE (component: Compiler). Supported versions that are affected are Oracle Java SE: 8u503-perf, 11.0.32.1, 17.0.20.1, 21.0.12.1, 25.0.4.1, 27; Oracle GraalVM for JDK: 17.0.20.1 and 21.0.12.1; Oracle GraalVM Enterprise Edition: 21.3.19.1.1. Difficult to exploit vulnerability allows unauthenticated attacker with network access via multiple protocols to compromise Oracle Java SE. Successful attacks of this vulnerability can result in unauthorized update, insert or delete access to some of Oracle Java SE accessible data as well as unauthorized read access to a subset of Oracle Java SE accessible data. Note: This vulnerability can only be exploited by supplying data to APIs in the specified Component without using Untrusted Java Web Start applications or Untrusted Java applets, such as through a web service. CVSS 3.1 Base Score 4.8 (Confidentiality and Integrity impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N).

It is possible to read the advisory at oracle.com. This vulnerability is known as CVE-2026-91487 since 09/15/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. The technical details are unknown and an exploit is not publicly available. The pricing for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 10/21/2026). The attack technique deployed by this issue is T1548.002 according to MITRE ATT&CK.

Upgrading eliminates this vulnerability.

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Productinfo

Type

• Programming Language Software

Vendor

• Oracle

Name

• Java SE

Version

• 8u503-perf
• 11.0.32.1
• 17.0.20.1
• 21.0.12.1
• 25.0.4.1
• 27

License

• open-source

Website

• Vendor: https://www.oracle.com

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