CVE-2026-91375: Auth Bypass (CVSS 4.7)

Description

Vulnerability in Oracle Java SE (component: Libraries). 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 logon to the infrastructure where Oracle Java SE executes to compromise Oracle Java SE. Successful attacks require human interaction from a person other than the attacker. Successful attacks of this vulnerability can result in unauthorized creation, deletion or modification access to critical data or all Oracle Java SE accessible data. Note: This vulnerability can be exploited by using APIs in the specified Component, e.g., through a web service which supplies data to the APIs. This vulnerability also applies to Java deployments, typically in clients running sandboxed Java Web Start applications or sandboxed Java applets, that load and run untrusted code (e.g., code that comes from the internet) and rely on the Java sandbox for security. CVSS 3.1 Base Score 4.7 (Integrity impacts). CVSS Vector: (CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N).

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CVSS v3.1 Score

4.7

MEDIUM

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

EPSS — Exploit Prediction

0.0009

Probability of exploitation

0.01%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-863 Incorrect Authorization

References

Other References

https://www.oracle.com/security-alerts/cpuoct2026.html

Frequently Asked Questions

What is CVE-2026-91375? +

Vulnerability in Oracle Java SE (component: Libraries). 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 logon to the infrastructure where Oracle Java SE executes to compromise Oracle Java SE. Successful attacks require human interaction from a person other than the attacker. Successful attacks of this vulnerability can result in unauthorized creation, deletion or modification access to critical data or all Oracle Java SE accessible data. Note: This vulnerability can be exploited by using APIs in the specified Component, e.g., through a web service which supplies data to the APIs. This vulnerability also applies to Java deployments, typically in clients running sandboxed Java Web Start applications or sandboxed Java applets, that load and run untrusted code (e.g., code that comes from the internet) and rely on the Java sandbox for security. CVSS 3.1 Base Score 4.7 (Integrity impacts). CVSS Vector: (CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N). It has a CVSS v3.1 base score of 4.7 (MEDIUM).

How severe is CVE-2026-91375? +

CVE-2026-91375 has a CVSS v3.1 score of 4.7 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0009, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-91375? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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