CVE-2020-27223Network attack vector

CPU exhaustion via quality-value sorting

Published Feb 26, 2021 · Updated Aug 20, 2025

Algorithmic-complexity DoS in Eclipse Jetty 9.4.6.v20170531 through 9.4.36.v20210114, 10.0.0, and 11.0.0 allows remote attackers to exhaust CPU. QuotedQualityCSV sorts attacker-controlled quality values from crafted Accept-family headers with inefficient worst-case behavior before dispatch. A single unauthenticated network request reaching default error handling or another listed consumer can occupy minutes of CPU time and interrupt service.

CVSS severity5.3
Medium
EPSS probability77.95%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Algorithmic-complexity DoS in Eclipse Jetty 9.4.6.v20170531 through 9.4.36.v20210114, 10.0.0, and 11.0.0 allows remote attackers to exhaust CPU. QuotedQualityCSV sorts attacker-controlled quality values from crafted Accept-family headers with inefficient worst-case behavior before dispatch. A single unauthenticated network request reaching default error handling or another listed consumer can occupy minutes of CPU time and interrupt service.

The record

CVE
CVE-2020-27223
Published
Feb 26, 2021
Updated
Aug 20, 2025
Vendor
The Eclipse Foundation
Product
Eclipse Jetty
Classifications
CWE-407, T1499.003
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 26, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 20, 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=10.0.0
  2. Affected versionversion=11.0.0
  3. Affected versionversion=9.4.6.v20170531 <unspecified
  4. Affected versionversion=unspecified <=9.4.36.v20210114

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Eclipse Foundation · Eclipse Jettyversion=10.0.0; version=11.0.0; version=9.4.6.v20170531 <unspecified; version=unspecified <=9.4.36.v20210114

Published CVSS scores

5.3GitHub Security AdvisoryCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

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-407Inefficient Algorithmic Complexity
T1499.003Application Exhaustion Flood

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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