CVE-2021-3312Public exploitNetwork attack vector

File disclosure via external entities in SVG parsing

Published Oct 8, 2021 · Updated Aug 3, 2024

XXE in Alkacon OpenCms 11.0 through 11.0.2 allows remote authenticated users to read server files through crafted SVG uploads. CmsResourceTypeImage.tryAddImageSizeFromSvg passed uploaded SVG bytes to SAXReader without CmsXmlEntityResolver, leaving external URL and file entities resolvable. Edit privileges and network access to the upload interface are required; successful exploitation discloses files readable by the OpenCms server process.

CVSS severity6.5
Medium
EPSS probability1.29%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

XXE in Alkacon OpenCms 11.0 through 11.0.2 allows remote authenticated users to read server files through crafted SVG uploads. CmsResourceTypeImage.tryAddImageSizeFromSvg passed uploaded SVG bytes to SAXReader without CmsXmlEntityResolver, leaving external URL and file entities resolvable. Edit privileges and network access to the upload interface are required; successful exploitation discloses files readable by the OpenCms server process.

The record

CVE
CVE-2021-3312
Published
Oct 8, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-611, T1005
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 8, 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

6.5NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
4.0NVDAV:N/AC:L/Au:S/C:P/I:N/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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-611Improper Restriction of XML External Entity Reference
T1005Data from Local System

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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