CVE-2026-12611Network attack vector

Server hang via HTTP/2 flusher race

Published Sep 8, 2026 · Updated Sep 9, 2026

Denial of service in Eclipse Jetty 9.4.36 through 12.1.10 allows remote attackers to hang HTTP/2 servers with crafted control frames. A race between RST_STREAM and GOAWAY handling resets HTTP2Flusher.terminated to null, so queued entries never run and blocked writes remain blocked. Any unauthenticated network client that can reach an enabled HTTP/2 connector can exhaust the server thread pool, leaving the service unresponsive.

CVSS severity8.7
High
EPSS probability0.25%
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 Eclipse Jetty 9.4.36 through 12.1.10 allows remote attackers to hang HTTP/2 servers with crafted control frames. A race between RST_STREAM and GOAWAY handling resets HTTP2Flusher.terminated to null, so queued entries never run and blocked writes remain blocked. Any unauthenticated network client that can reach an enabled HTTP/2 connector can exhaust the server thread pool, leaving the service unresponsive.

The record

CVE
CVE-2026-12611
Published
Sep 8, 2026
Updated
Sep 9, 2026
Vendor
The Eclipse Foundation
Product
Eclipse Jetty
Classifications
CWE-400, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 8, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 9, 2026Record 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=10.0.0 <=10.0.31
  2. Affected versionversion=11.00 <=11.0.31
  3. Affected versionversion=12.0.0 <=12.0.37
  4. Affected versionversion=12.1.0 <=12.1.10
  5. Affected versionversion=9.4.36 <=9.4.63

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Eclipse Foundation · Eclipse Jettyversion=10.0.0 <=10.0.31; version=11.00 <=11.0.31; version=12.0.0 <=12.0.37; version=12.1.0 <=12.1.10; version=9.4.36 <=9.4.63

Published CVSS scores

8.7Eclipse FoundationCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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 exploitUnconfirmed

Weakness, pattern, technique

CWE-400Uncontrolled Resource Consumption
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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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