CVE-2021-3841Public exploitNetwork attack vector

Stored XSS via unsanitized SVG uploads

Published Nov 15, 2024 · Updated Nov 20, 2024

Stored XSS in Sylius before 1.9.10, 1.10.0 through 1.10.10, and 1.11.0 through 1.11.1 allows attackers to run browser scripts. The ImageUploader writes SVG image content to its filesystem without sanitizing embedded script markup. Admin-panel upload access is required, and the code executes only when the SVG is opened in a new tab or loaded outside an image tag on admin or shop pages.

CVSS severity4.1
Medium
EPSS probability0.25%
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 Sylius before 1.9.10, 1.10.0 through 1.10.10, and 1.11.0 through 1.11.1 allows attackers to run browser scripts. The ImageUploader writes SVG image content to its filesystem without sanitizing embedded script markup. Admin-panel upload access is required, and the code executes only when the SVG is opened in a new tab or loaded outside an image tag on admin or shop pages.

The record

CVE
CVE-2021-3841
Published
Nov 15, 2024
Updated
Nov 20, 2024
Vendor
Sylius
Product
Sylius
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Nov 15, 2024CVE publishedPublication date reported by the CVE source.
  2. Nov 20, 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=unspecified <1.9.10, 1.10.11, 1.11.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

Sylius · Syliusversion=unspecified <1.9.10, 1.10.11, 1.11.2

Published CVSS scores

5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
4.1huntr.devCVSS:3.0/AV:N/AC:H/PR:H/UI:N/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesadmin
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/JScript

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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