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Fencer Vulns
high 7.5

CVE-2026-6918 json

In Eclipse Open9J versions 0.21 to 0.58, a pre-authentication remote attacker can crash JITServer by sending a 32-byte crafted TCP message.

published 2026-05-05 6 mo ago modified 2026-10-26 13 d ago also EUVD-2026-27315

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 44%
public exploits
0
none known

Summary

In Eclipse Open9J versions 0.21 to 0.58, a pre-authentication remote attacker can crash JITServer by sending a 32-byte crafted TCP message.

Patch / fix

  • Eclipse Foundation Eclipse OpenJ9 0.59
  • Red Hat Red Hat Enterprise Linux 10 1:21.0.11.0.10-2.el10_1
  • Red Hat Red Hat Enterprise Linux 10.0 Extended Update Support 1:21.0.11.0.10-1.el10_0
  • Red Hat Red Hat Enterprise Linux 10.2 Extended Update Support 1:21.0.11.0.10-2.el10_1
  • java-21-ibm-semeru-certified-jdk RHEL 10.2, enterprise linux eus 10.2 1:21.0.11.0.10-2.el10_1
  • java-21-ibm-semeru-certified-jdk-src RHEL 10.2, enterprise linux eus 10.2 1:21.0.11.0.10-2.el10_1
  • java-21-ibm-semeru-certified-jdk-jmods RHEL 10.2, enterprise linux eus 10.2 1:21.0.11.0.10-2.el10_1
  • java-21-ibm-semeru-certified-jdk-headless RHEL 10.2, enterprise linux eus 10.2 1:21.0.11.0.10-2.el10_1
  • java-21-ibm-semeru-certified-jdk enterprise linux eus 10.0 1:21.0.11.0.10-1.el10_0
  • java-21-ibm-semeru-certified-jdk-headless enterprise linux eus 10.0 1:21.0.11.0.10-1.el10_0

red hat advisories RHSA-2026:22328

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-6918 updated cvss 7.5

Eclipse Open9J: Denial of Service in JITServer via crafted TCP message

  • Red Hat Enterprise Linux Supplementary (v. 10) java-21-ibm-semeru-certified-jdk 21.0.11.0.10-2.el10_1, java-21-ibm-semeru-certified-jdk-src 21.0.11.0.10-2.el10_1, java-21-ibm-semeru-certified-jdk-jmods 21.0.11.0.10-2.el10_1, java-21-ibm-semeru-certified-jdk-headless 21.0.11.0.10-2.el10_1 Red Hat Enterprise Linux Supplementary EUS (v. 10.0) java-21-ibm-semeru-certified-jdk 21.0.11.0.10-1.el10_0, java-21-ibm-semeru-certified-jdk-headless 21.0.11.0.10-1.el10_0 Red Hat Enterprise Linux Supplementary EUS (v.10.2) java-21-ibm-semeru-certified-jdk 21.0.11.0.10-2.el10_1, java-21-ibm-semeru-certified-jdk-src 21.0.11.0.10-2.el10_1, java-21-ibm-semeru-certified-jdk-jmods 21.0.11.0.10-2.el10_1, java-21-ibm-semeru-certified-jdk-headless 21.0.11.0.10-2.el10_1
    fixed: vendor fix RHSA-2026:22328

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
6 mo ago

Exploit prediction

0.52% chance of exploitation in the next 30 days, higher than 44% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/eclipse-openj9/openj9/security/advisories/GHSA-q393-vr4c-969r referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 8.7 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CISA ADP 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA 4.0 8.7 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Eclipse Foundation Eclipse OpenJ9
  • Red Hat Red Hat Enterprise Linux 10
  • Red Hat Red Hat Enterprise Linux 10.0 Extended Update Support
  • Red Hat Red Hat Enterprise Linux 10.2 Extended Update Support

Classification

Weakness
  • CWE-125 Out-of-bounds Read
  • CWE-1286 Improper Validation of Syntactic Correctness of Input

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.