CVE-2021-33496Network attack vector

Cross-site scripting via incomplete inline content sanitization

Published May 24, 2021 · Updated Aug 3, 2024

Cross-site scripting in Dutchcoders transfer.sh before 1.2.4 allows remote attackers to execute scripts through an inline file view. The upload handlers trusted client-supplied Content-Type metadata, while getHandler sanitized inline responses only when that value contained HTML. A victim must open the crafted file inline; the script then runs in the service's origin and can read browser-accessible data or perform actions as the victim.

CVSS severity6.1
Medium
EPSS probability1.01%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in Dutchcoders transfer.sh before 1.2.4 allows remote attackers to execute scripts through an inline file view. The upload handlers trusted client-supplied Content-Type metadata, while getHandler sanitized inline responses only when that value contained HTML. A victim must open the crafted file inline; the script then runs in the service's origin and can read browser-accessible data or perform actions as the victim.

The record

CVE
CVE-2021-33496
Published
May 24, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-79, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 24, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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 privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

6.1GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:N/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.

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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
Privilegesunauthenticated
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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