CVE-2020-9481Network attack vector

Service interruption via slow HTTP/2 reads

Published Apr 27, 2020 · Updated Aug 4, 2024

Denial of service in Apache Traffic Server allows remote attackers to interrupt proxy service via slow HTTP/2 reads. The affected releases are 6.0.0 through 6.2.3, 7.0.0 through 7.1.9, and 8.0.0 through 8.0.6; Apache has not published the flawed HTTP/2 code path. An unauthenticated network client must keep response reads slow enough to consume server resources, degrading availability without reported data exposure or modification.

CVSS severity7.5
High
EPSS probability2.39%
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 Apache Traffic Server allows remote attackers to interrupt proxy service via slow HTTP/2 reads. The affected releases are 6.0.0 through 6.2.3, 7.0.0 through 7.1.9, and 8.0.0 through 8.0.6; Apache has not published the flawed HTTP/2 code path. An unauthenticated network client must keep response reads slow enough to consume server resources, degrading availability without reported data exposure or modification.

The record

CVE
CVE-2020-9481
Published
Apr 27, 2020
Updated
Aug 4, 2024
Vendor
Apache Software Foundation
Product
Apache Traffic Server
Classifications
CWE-400, T1498.003
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 27, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record 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=6.0.0 to 6.2.3
  2. Affected versionversion=7.0.0 to 7.1.9
  3. Affected versionversion=8.0.0 to 8.0.6

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Apache Software Foundation · Apache Traffic Serverversion=6.0.0 to 6.2.3; version=7.0.0 to 7.1.9; version=8.0.0 to 8.0.6

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:N/A:P

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 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
T1498.003Network Denial of Service: Application 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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