CVE-2020-8281Public exploitNetwork attack vector

Stored XSS via unchecked SVG image upload

Published Jan 6, 2021 · Updated Aug 4, 2024

Stored XSS in Nextcloud Contacts before 3.4.0 allows remote authenticated users to execute script through a malicious SVG contact image. Contacts accepts an uploaded SVG contact image without checking its file type, stores it, and later serves the active image content to another user's browser. An account capable of changing a contact image and a victim who views the affected contact are required; script runs in the Nextcloud origin.

CVSS severity5.4
Medium
EPSS probability0.62%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in Nextcloud Contacts before 3.4.0 allows remote authenticated users to execute script through a malicious SVG contact image. Contacts accepts an uploaded SVG contact image without checking its file type, stores it, and later serves the active image content to another user's browser. An account capable of changing a contact image and a victim who views the affected contact are required; script runs in the Nextcloud origin.

The record

CVE
CVE-2020-8281
Published
Jan 6, 2021
Updated
Aug 4, 2024
Vendor
Nextcloud GmbH
Product
Nextcloud Contacts
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 6, 2021CVE 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=Fixed in 3.4.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Nextcloud GmbH · Nextcloud Contactsversion=Fixed in 3.4.0

Published CVSS scores

5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
5.5NextcloudCVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1059.007Command and Scripting Interpreter: JavaScript

Public exploit references

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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