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Stored Cross Site Scripting with SVG image in user portrait

Low
mauritsvanrees published GHSA-hc5c-r8m5-2gfh Sep 21, 2023

Package

pip plone.restapi (pip)

Affected versions

>8.0.0,<=8.43.2

Patched versions

8.43.3

Description

Impact

There is a stored cross site scripting vulnerability for SVG images uploaded in user portraits.

Note that a page that uses an image tag with an SVG image as source is never vulnerable, even when the SVG image contains malicious code. To exploit the vulnerability, an attacker would first need to upload an SVG image as user portrait, and then trick a user into following a link to this portrait.

Patches

A patch will be released in plone.restapi 8.43.3. This version is good for Plone 6.0, and for Plone 5.2 on Python 3.

In plone.restapi 7 or earlier there was no @portrait endpoint yet, so there is nothing to fix in that version. It is still vulnerable to this attack, and needs a fix in Zope 4. These two vulnerabilities share the same CVE: CVE-2023-42458.

Workarounds

You could remove the portrait field from the member data schema, and possibly remove all portraits that are already in the database, but this seems a bit drastic.

Credits

This was independently reported to the Plone Security Team by Gustav Hansen and Faris Krivic. Thanks!

Severity

Low

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
High
Privileges required
Low
User interaction
Required
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:L/A:N

CVE ID

CVE-2023-42458

Weaknesses