Security Digest · Vulnerability record
CVE-2026-91403: Oracle Corporation Oracle Java SE vulnerability
Vulnerability in the Oracle Java SE, Oracle GraalVM for JDK, Oracle GraalVM Enterprise Edition product of Oracle Java SE (component: JSSE).
CVSS 9.1 Critical Patch this week
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. That can change quickly after a public write-up; re-check if you are affected.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Editorial verdict: Patch this week. eMudhra CA Key Compromise: Update Non-Browser TLS Clients — Anyone can mint certificates from these broken CA keys, but only clients that skip Certificate Transparency and still trust the emSign root are exposed, and only to an on-path attacker: update those trust bundles this week, build machines first.
What it is
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).
Product: Oracle Corporation Oracle Java SE · Assigned by: oracle · Published: 2026-10-21
Affected and fixed versions
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| Oracle Corporation | Oracle Java SE | 8u511, 8u511-perf, 11.0.33, 17.0.21, 21.0.13, 25.0.5, 27.0.1 |
| Oracle Corporation | Oracle GraalVM for JDK | 17.0.21, 21.0.13 |
| Oracle Corporation | Oracle GraalVM Enterprise Edition | 21.3.20 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| oracle | 3.1 | 9.1 Critical | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N |
- 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).
Timeline
- — erroneo.us brief: eMudhra CA Key Compromise: Update Non-Browser TLS Clients
- — CVE record last updated
- — CVE record published by oracle
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vendor and project advisories, patches
- Oracle Advisory oracle.com
Vulnerability records
- CVE.org record CVE-2026-91403 cve.org
- NVD entry CVE-2026-91403 nvd.nist.gov