CVE-2025-66561Network attack vector

Authenticated session compromise via inline uploaded scripts

Published Dec 4, 2025 · Updated Dec 5, 2025

Stored XSS in Syslifters GmbH SysReptor before 2025.102 allows remote authenticated users to execute JavaScript in another logged-in user's session. Django FileResponse derives an executable content type from an uploaded file's extension, while inline disposition lets uploaded HTML load same-origin JavaScript despite the content policy. Exploitation requires an uploaded payload and a logged-in victim opening its direct URL; normal web-interface navigation does not trigger it.

CVSS severity7.3
High
EPSS probability0.19%
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 Syslifters GmbH SysReptor before 2025.102 allows remote authenticated users to execute JavaScript in another logged-in user's session. Django FileResponse derives an executable content type from an uploaded file's extension, while inline disposition lets uploaded HTML load same-origin JavaScript despite the content policy. Exploitation requires an uploaded payload and a logged-in victim opening its direct URL; normal web-interface navigation does not trigger it.

The record

CVE
CVE-2025-66561
Published
Dec 4, 2025
Updated
Dec 5, 2025
Vendor
Syslifters GmbH
Product
SysReptor
Classifications
CWE-79, T1203
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 4, 2025CVE publishedPublication date reported by the CVE source.
  2. Dec 5, 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=< 2025.102

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Syslifters GmbH · SysReptorversion=< 2025.102

Published CVSS scores

7.3GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N
5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/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 exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1203Exploitation for Client Execution

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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