Oracle emergency Java update distrusts weak eMudhra CAs (CVE-2026-91403)
The CVSS 9.1 JSSE flaw can let an on-path attacker forge trusted hostnames; no attacks are confirmed.
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Vulnerability3 · 1 read
CVE-2026-91403
JSSE trust flaw in Oracle Java SE and GraalVM
- CVSS 3.1
- 9.1 critical
- EPSS
- —
- Published
- ·
- Modified
AI analysisSummaries by Vani AI
A flaw in the JSSE component of Oracle Java SE, GraalVM for JDK, and GraalVM Enterprise Edition lets an unauthenticated attacker on the network, using multiple protocols and no user interaction, read, create, change, or delete critical data those runtimes can access. It can be triggered through JSSE APIs, including a web service that supplies data, and also through sandboxed Java Web Start apps or applets that load untrusted code. Listed Java SE, GraalVM for JDK, and GraalVM Enterprise builds are affected.
What to do: Apply Oracle's update for CVE-2026-91403. Oracle has not listed fixed build numbers in the affected-version notice.
| Product | Affected |
|---|---|
| Oracle Java SE | 8u511, 8u511-perf, 11.0.33, 17.0.21, 21.0.13, 25.0.5, 27.0.1 |
| Oracle GraalVM for JDK | 17.0.21, 21.0.13 |
| Oracle GraalVM Enterprise Edition | 21.3.20 |
Estimated exposure
massMillions of Java SE and GraalVM hosts — Java SE is widely deployed; the flaw is reachable over the network without authentication via JSSE.
Order-of-magnitude estimate by the model from install counts, market share and public scan data it knows; verify before quoting.
Description · NVD
Vulnerability in the Oracle Java SE, Oracle GraalVM for JDK, Oracle GraalVM Enterprise Edition product of Oracle Java SE (component: JSSE). Supported versions that are affected are Oracle Java SE: 8u511, 8u511-perf, 11.0.33, 17.0.21, 21.0.13, 25.0.5, 27.0.1; Oracle GraalVM for JDK: 17.0.21 and 21.0.13; Oracle GraalVM Enterprise Edition: 21.3.20. Easily exploitable vulnerability allows unauthenticated attacker with network access via multiple protocols to compromise Oracle Java SE, Oracle GraalVM for JDK, Oracle GraalVM Enterprise Edition. Successful attacks of this vulnerability can result in unauthorized creation, deletion or modification access to critical data or all Oracle Java SE, Oracle GraalVM for JDK, Oracle GraalVM Enterprise Edition accessible data as well as unauthorized access to critical data or complete access to all Oracle Java SE, Oracle GraalVM for JDK, Oracle GraalVM Enterprise Edition 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 9.1 (Confidentiality and Integrity impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N).
- Weakness
- CWE-327
- Vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
In the news
4 storiesOracle Java flaw CVE-2026-91403 allows unauthenticated remote attacks
The CVSS 9.1 JSSE issue concerns trust in compromised eMudhra intermediate certificates, not confirmed code execution.
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Oracle alerts on unauthenticated Java JSSE flaw CVE-2026-91403
The CVSS 9.1 issue affects named Java SE and GraalVM builds and can be reached through JSSE APIs without credentials.
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