CVE-2020-12853Public exploitNetwork attack vector

Stored XSS via inline uploaded HTML files

Published Jun 4, 2020 · Updated Aug 4, 2024

Stored XSS in Pydio Cells 2.0.4 allows remote authenticated users to execute JavaScript in another user's session through a crafted file URL. The download endpoint reflects response-content-disposition and response-content-type URL parameters into response headers, causing stored attacker HTML to render inline. An attacker needs file access, a valid short-lived JWT in the link, and an authenticated victim who opens it; the script inherits the victim's session privileges.

CVSS severity6.1
Medium
EPSS probability0.76%
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 Pydio Cells 2.0.4 allows remote authenticated users to execute JavaScript in another user's session through a crafted file URL. The download endpoint reflects response-content-disposition and response-content-type URL parameters into response headers, causing stored attacker HTML to render inline. An attacker needs file access, a valid short-lived JWT in the link, and an authenticated victim who opens it; the script inherits the victim's session privileges.

The record

CVE
CVE-2020-12853
Published
Jun 4, 2020
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-79, T1204.001
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 4, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

6.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:P/A: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 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 exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1204.001Malicious Link

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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