CVE-2026-39304

HIGHPre-NVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.5 under NVD CVSS v3. EPSS exploit probability: 0.1%, top 82% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
7.5
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 1%CVSS: 7.5Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

Denial of Service via Out of Memory vulnerability in Apache ActiveMQ Client, Apache ActiveMQ Broker, Apache ActiveMQ.

ActiveMQ NIO SSL transports do not correctly handle TLSv1.3 handshake KeyUpdates triggered by clients. This makes it possible for a client to rapidly trigger updates which causes the broker to exhaust all its memory in the SSL engine leading to DoS.

Note: TLS versions before TLSv1.3 (such as TLSv1.2) are broken but are not vulnerable to OOM. Previous TLS versions require a full handshake renegotiation which causes a connection to hang but not OOM. This is fixed as well. This issue affects Apache ActiveMQ Client: before 5.19.4, from 6.0.0 before 6.2.4; Apache ActiveMQ Broker: before 5.19.4, from 6.0.0 before 6.2.4; Apache ActiveMQ: before 5.19.4, from 6.0.0 before 6.2.4.

Users are recommended to upgrade to version 6.2.4 or 5.19.5, which fixes the issue.

CVSS v3
7.5
EG Score
7.5(medium)
EPSS
55.3%
KEV
Not listed

Published

April 10, 2026

Last Modified

June 30, 2026

Advisory Details (2)

Auto-updated May 1, 2026
No patch confirmed yet.
generic

oss-security - CVE-2026-39304: Apache ActiveMQ Client, Apache ActiveMQ Broker, Apache ActiveMQ All, Apache ActiveMQ: Incorrect handling of TLSv1.3 KeyUpdate can be exploited to cause DoS via OOM

http://www.openwall.com/lists/oss-security/2026/04/09/17
generic
https://activemq.apache.org/security-advisories.data/CVE-2026-39304-announcement.txt

Affected Packages

(4 across 1 ecosystem)
Maven(4)
PackageVulnerable rangeFixed inDependents
org.apache.activemq:activemq-all6.0.0 ... 6.2.3 (15 versions)6.2.4—
org.apache.activemq:activemq-broker6.0.0 ... 6.2.3 (15 versions)6.2.4—
org.apache.activemq:activemq-client6.0.0 ... 6.2.3 (15 versions)6.2.4—
org.apache.activemq:apache-activemq6.0.0 ... 6.2.3 (15 versions)6.2.4—

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 9× in last 7d / 37× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-11 08:27 UTCEPSS rescore
  2. 2026-07-09 19:10 UTCEPSS rescore
  3. 2026-07-08 15:15 UTCEPSS rescore
  4. 2026-07-07 13:46 UTCEPSS rescore
  5. 2026-07-06 16:27 UTCEPSS rescore
  6. 2026-07-06 16:27 UTCEPSS rescore
  7. 2026-07-06 02:23 UTCEPSS rescore
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  9. 2026-07-05 02:30 UTCEPSS rescore
  10. 2026-07-04 06:31 UTCEPSS rescore
  11. 2026-07-01 15:06 UTCEPSS rescore
  12. 2026-06-30 23:22 UTCEPSS rescore
  13. 2026-06-29 14:06 UTCEPSS rescore
  14. 2026-06-28 14:07 UTCEPSS rescore
  15. 2026-06-28 04:56 UTCEPSS rescore
  16. 2026-06-27 03:08 UTCEPSS rescore
  17. 2026-06-25 13:49 UTCEPSS rescore
  18. 2026-06-25 13:49 UTCEPSS rescore
  19. 2026-06-24 14:05 UTCEPSS rescore
  20. 2026-06-23 21:33 UTCEPSS rescore
  21. 2026-06-22 14:25 UTCEPSS rescore
  22. 2026-06-22 14:25 UTCEPSS rescore
  23. 2026-06-21 14:56 UTCEPSS rescore
  24. 2026-06-21 14:56 UTCEPSS rescore
  25. 2026-06-21 01:59 UTCEPSS rescore
Show 61 more
  1. 2026-06-19 19:25 UTCEPSS rescore
  2. 2026-06-19 19:25 UTCEPSS rescore
  3. 2026-06-18 17:52 UTCEPSS rescore
  4. 2026-06-18 17:52 UTCEPSS rescore
  5. 2026-06-17 17:53 UTCEPSS rescore
  6. 2026-06-16 17:52 UTCEPSS rescore
  7. 2026-06-15 17:49 UTCEPSS rescore
  8. 2026-06-15 04:25 UTCEG score recompute
  9. 2026-06-14 23:18 UTCEPSS rescore
  10. 2026-06-13 23:00 UTCEPSS rescore
  11. 2026-06-12 23:12 UTCEPSS rescore
  12. 2026-06-12 23:12 UTCEPSS rescore
  13. 2026-06-11 20:12 UTCEG score recompute
  14. 2026-06-11 14:00 UTCEPSS rescore
  15. 2026-06-10 22:18 UTCEPSS rescore
  16. 2026-06-10 14:44 UTCEG score recompute
  17. 2026-06-10 13:22 UTCEPSS rescore
  18. 2026-06-10 01:44 UTCEG score recompute
  19. 2026-06-09 12:44 UTCEG score recompute
  20. 2026-06-08 14:17 UTCEPSS rescore
  21. 2026-06-08 14:17 UTCEPSS rescore
  22. 2026-06-08 10:22 UTCEG score recompute
  23. 2026-06-07 21:11 UTCEG score recompute
  24. 2026-06-07 15:25 UTCEPSS rescore
  25. 2026-06-07 15:25 UTCEPSS rescore
  26. 2026-06-07 15:25 UTCEPSS rescore
  27. 2026-06-07 08:11 UTCEG score recompute
  28. 2026-06-06 13:47 UTCEPSS rescore
  29. 2026-06-06 13:47 UTCEPSS rescore
  30. 2026-06-05 22:47 UTCEPSS rescore
  31. 2026-06-05 22:47 UTCEPSS rescore
  32. 2026-06-05 06:10 UTCEPSS rescore
  33. 2026-06-05 06:10 UTCEPSS rescore
  34. 2026-06-04 13:12 UTCEPSS rescore
  35. 2026-06-04 13:12 UTCEPSS rescore
  36. 2026-06-02 20:13 UTCEPSS rescore
  37. 2026-06-01 13:52 UTCEPSS rescore
  38. 2026-06-01 13:52 UTCEPSS rescore
  39. 2026-06-01 13:51 UTCEPSS rescore
  40. 2026-05-31 22:30 UTCEPSS rescore
  41. 2026-05-31 22:30 UTCEPSS rescore
  42. 2026-05-31 00:16 UTCEPSS rescore
  43. 2026-05-31 00:16 UTCEPSS rescore
  44. 2026-05-31 00:16 UTCEPSS rescore
  45. 2026-05-29 13:44 UTCEPSS rescore
  46. 2026-05-29 13:44 UTCEPSS rescore
  47. 2026-05-28 13:44 UTCEPSS rescore
  48. 2026-05-28 13:44 UTCEPSS rescore
  49. 2026-05-28 13:44 UTCEPSS rescore
  50. 2026-05-27 13:40 UTCEPSS rescore
  51. 2026-05-27 13:40 UTCEPSS rescore
  52. 2026-05-27 13:40 UTCEPSS rescore
  53. 2026-05-26 13:44 UTCEPSS rescore
  54. 2026-05-26 07:18 UTCEPSS rescore
  55. 2026-05-26 07:18 UTCEPSS rescore
  56. 2026-05-23 00:08 UTCEG score recompute
  57. 2026-05-20 22:38 UTCEPSS rescore
  58. 2026-05-20 22:38 UTCEPSS rescore
  59. 2026-05-20 17:54 UTCEG score recompute
  60. 2026-05-20 11:22 UTCEPSS rescore
  61. 2026-05-20 11:22 UTCEPSS rescore

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-39304?
CVE-2026-39304 is a high vulnerability published on April 10, 2026. Denial of Service via Out of Memory vulnerability in Apache ActiveMQ Client, Apache ActiveMQ Broker, Apache ActiveMQ. ActiveMQ NIO SSL transports do not correctly handle TLSv1.3 handshake KeyUpdates triggered by clients. This makes it possible for a client to rapidly trigger updates which causes…
When was CVE-2026-39304 disclosed?
CVE-2026-39304 was first published in the National Vulnerability Database on April 10, 2026, with the most recent update on June 30, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-39304 actively exploited?
CVE-2026-39304 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 55.3% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-39304?
CVE-2026-39304 has a CVSS v3.1 base score of 7.5 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-39304?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-39304, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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