CVE-2021-3395Public exploitNetwork attack vector

Authenticated XSS via arbitrary file upload

Published Feb 2, 2021 · Updated Aug 3, 2024

Cross-site scripting in Pryaniki 6.44.3 allows remote authenticated users to upload an arbitrary file that executes JavaScript when an attachment is viewed. The upload path stores attacker-controlled HTML or script content without preventing browser execution when another user opens the attachment. Exploitation requires authenticated remote access to file upload and a victim to visit the crafted attachment, producing script execution with the victim's web-session context.

CVSS severity5.4
Medium
EPSS probability0.75%
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 Pryaniki 6.44.3 allows remote authenticated users to upload an arbitrary file that executes JavaScript when an attachment is viewed. The upload path stores attacker-controlled HTML or script content without preventing browser execution when another user opens the attachment. Exploitation requires authenticated remote access to file upload and a victim to visit the crafted attachment, producing script execution with the victim's web-session context.

The record

CVE
CVE-2021-3395
Published
Feb 2, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-79, T1189
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 2, 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 privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

5.4NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
3.5NVDAV:N/AC:M/Au:S/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')
T1189Drive-by Compromise

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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