Medium

CVE-2026-91453 — Vulnerability in the Oracle Java SE, Oracle GraalVM for JDK, Oracle GraalVM Enterprise Edition...

Vulnerability in the Oracle Java SE, Oracle GraalVM for JDK, Oracle GraalVM Enterprise Edition product of Oracle Java SE (component: Lightweight HTTP Server). Supported versions that are affected are Oracle Java SE: 8u503, 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. 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 update, insert or delete access to some of Oracle Java SE, Oracle GraalVM for JDK, Oracle GraalVM Enterprise Edition 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 5.3 (Integrity impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N).

Published Oct 20, 2026 · Updated Oct 21, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP, GitHub Security Advisories · CNA: oracle

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

EPSS 0.3% (30-day exploitation probability)+3
Technical severity (medium)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

0.3%

ahead of 21% of scored CVEs · Oct 21, 2026

Affects

Oracle

Graalvm For Jdk and 2 more

CVSS base

5.3

Medium · 3 source(s)

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Oracle Graalvm For Jdk, Oracle Java Se, Oracle Oracle GraalVM Enterprise Edition).
The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Oracle	Graalvm For Jdk	version 17.0.20.1version 21.0.12.1	Vulnerable	CVE Program (cve.org) e CISA ADP
Oracle	Java Se	version 8u503version 8u503-perfversion 11.0.32.1version 17.0.20.1version 21.0.12.1version 25.0.4.1version 27	Vulnerable	CVE Program (cve.org) e CISA ADP
Oracle	Oracle GraalVM Enterprise Edition	version 21.3.19.1.1	Vulnerable	CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Network

Attack complexity

Low

Privileges required

None

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

Low

Availability

None

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
5.3	CVSS 3.1	Medium	3.9	1.4	secalert_us@oracle.com via NIST National Vulnerability Database
5.3	CVSS 3.1	Medium	—	—	GitHub, Inc. via GitHub Security Advisories
5.3	CVSS 3.1	Medium	—	—	oracle via CVE Program (cve.org) e CISA ADP

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N (score shown at the top: secalert_us@oracle.com)

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).

web/proxy/WAF logsnetwork IDS/IPS

Timeline

What happened to this CVE, newest first.

2026
Source status changed · Received → Awaiting Analysis
Oct 21, 2026 · NIST National Vulnerability Database
Affected products added · oracle corporation/oracle java se, oracle corporation/oracle graalvm for jdk, oracle corporation/oracle graalvm enterpri
Oct 20, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 20, 2026
CVSS changed · 5.3
Oct 20, 2026 · NIST National Vulnerability Database
Source status changed · → Received
Oct 20, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 20, 2026 · NIST National Vulnerability Database
CVE published
Oct 20, 2026 · oracle

Source activity

Repeated readings are counted rather than listed.

1× References added · Oct 21, 2026 – Oct 21, 2026
1× Official description updated · Oct 20, 2026 – Oct 20, 2026

References

3 on the record

github.com/advisories/GHSA-wh5x-8c26-q7r3
GitHub Security Advisories
nvd.nist.gov/vuln/detail/CVE-2026-91453
GitHub Security Advisories
www.oracle.com/security-alerts/cpuoct2026.html
vendor-advisory, NIST National Vulnerability Database

Elsewhere on this site

Oracle
every CVE for this vendor

Related CVEs (same products)

Critical CVE-2026-91403 Vulnerability in the Oracle Java SE, Oracle GraalVM for JDK, Oracle GraalVM Enterprise… 1h
Medium CVE-2026-91487 Vulnerability in Oracle Java SE (component: Compiler). Supported versions that are affected are... 1d
High CVE-2026-91484 Vulnerability in Oracle Java SE (component: Java plugin). Supported versions that are affected... 1d
Medium CVE-2026-91464 Vulnerability in the Oracle Java SE, Oracle GraalVM for JDK, Oracle GraalVM Enterprise Edition... 1d
Medium CVE-2026-91463 Vulnerability in the Oracle Java SE, Oracle GraalVM for JDK, Oracle GraalVM Enterprise Edition... 1d
Medium CVE-2026-91462 Vulnerability in the Oracle Java SE, Oracle GraalVM for JDK, Oracle GraalVM Enterprise Edition... 1d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No fixed version, patch or mitigation documented.
No CISA SSVC assessment.
No CWE classification.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-91453 is "Vulnerability in the Oracle Java SE, Oracle GraalVM for JDK, Oracle GraalVM Enterprise Edition...", rated Medium. It affects Graalvm For Jdk (Oracle); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 5.3 describes technical severity. EPSS 0.30% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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