CVE-2020-29450Network attack vector

Remote DoS via oversized avatar upload

Published Jan 19, 2021 · Updated Sep 16, 2024

Denial of Service in Atlassian Confluence Server before 7.2.0 allows remote attackers to interrupt service via avatar upload. The avatar upload handler accepts excessively large avatar data and consumes application resources until Confluence becomes unavailable. The attack reaches the network-facing upload feature and requires the ability to submit an avatar; impact is service interruption without reported data disclosure or modification.

CVSS severity6.5
Medium
EPSS probability2.21%
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 Atlassian Confluence Server before 7.2.0 allows remote attackers to interrupt service via avatar upload. The avatar upload handler accepts excessively large avatar data and consumes application resources until Confluence becomes unavailable. The attack reaches the network-facing upload feature and requires the ability to submit an avatar; impact is service interruption without reported data disclosure or modification.

The record

CVE
CVE-2020-29450
Published
Jan 19, 2021
Updated
Sep 16, 2024
Vendor
Atlassian
Product
Confluence Server
Classifications
CWE-434, T1499
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 19, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 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=unspecified <7.2.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Atlassian · Confluence Serverversion=unspecified <7.2.0

Published CVSS scores

4.0NVDAV:N/AC:L/Au:S/C:N/I:N/A:P
6.5NVDCVSS:3.1/AV:N/AC:L/PR:L/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.

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-434Unrestricted Upload of File with Dangerous Type
T1499Endpoint Denial of Service

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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