CVE-2023-21967Public exploitNetwork attack vector

Denial of service via certificate-path recursion

Published Apr 18, 2023 · Updated Feb 13, 2025

Denial of service in Oracle Java SE 8u361, 8u361-perf, 11.0.18, 17.0.6, and 20 allows remote attackers to hang or crash JSSE over HTTPS. ForwardBuilder treats only byte-identical certificates as repeats, so crafted certificates with shared subjects and keys cause combinatorial PKIX path exploration. Reachability requires untrusted certificate chains supplied during HTTPS negotiation through sandboxed code or an API-consuming service; successful exploitation interrupts the affected Java process.

CVSS severity5.9
Medium
EPSS probability1.54%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Oracle Java SE 8u361, 8u361-perf, 11.0.18, 17.0.6, and 20 allows remote attackers to hang or crash JSSE over HTTPS. ForwardBuilder treats only byte-identical certificates as repeats, so crafted certificates with shared subjects and keys cause combinatorial PKIX path exploration. Reachability requires untrusted certificate chains supplied during HTTPS negotiation through sandboxed code or an API-consuming service; successful exploitation interrupts the affected Java process.

The record

CVE
CVE-2023-21967
Published
Apr 18, 2023
Updated
Feb 13, 2025
Vendor
Oracle Corporation
Product
Java Platform, Standard Edition (Java SE)
Classifications
T1499.003
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 18, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 13, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=Oracle GraalVM Enterprise Edition:20.3.9
  2. Affected versionversion=Oracle GraalVM Enterprise Edition:21.3.5
  3. Affected versionversion=Oracle GraalVM Enterprise Edition:22.3.1
  4. Affected versionversion=Oracle Java SE:11.0.18
  5. Affected versionversion=Oracle Java SE:17.0.6
  6. Affected versionversion=Oracle Java SE:20
  7. Affected versionversion=Oracle Java SE:8u361
  8. Affected versionversion=Oracle Java SE:8u361-perf

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Oracle Corporation · Java Platform, Standard Edition (Java SE)version=Oracle GraalVM Enterprise Edition:20.3.9; version=Oracle GraalVM Enterprise Edition:21.3.5; version=Oracle GraalVM Enterprise Edition:22.3.1; version=Oracle Java SE:11.0.18; version=Oracle Java SE:17.0.6; version=Oracle Java SE:20; version=Oracle Java SE:8u361; version=Oracle Java SE:8u361-perf

Published CVSS scores

5.9Oracle CorporationCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

T1499.003Application Exhaustion Flood

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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