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malicious SVG attachment causing stored XSS vulnerability

High severity GitHub Reviewed Published Nov 8, 2020 in moinwiki/moin-1.9 • Updated Jan 31, 2023

Package

pip moin (pip)

Affected versions

< 1.9.11

Patched versions

1.9.11

Description

Impact

An attacker with write permissions can upload an SVG file that contains malicious javascript. This javascript will be executed in a user's browser when the user is viewing that SVG file on the wiki.

Patches

Users are strongly advised to upgrade to a patched version.

MoinMoin Wiki 1.9.11 has the necessary fixes and also contains other important fixes.

Workarounds

It is not advised to work around this, but to upgrade MoinMoin to a patched version.

That said, a work around via a Content Security Policy in the web server might be possible.

Also, it is of course helpful if you give write permissions (which include uploading attachments) only to trusted users.

For more information

If you have any questions or comments about this advisory, email me at twaldmann@thinkmo.de.

Credits

This vulnerability was discovered by:

Catarina Leite from the Checkmarx SCA AppSec team

References

@ThomasWaldmann ThomasWaldmann published to moinwiki/moin-1.9 Nov 8, 2020
Reviewed Nov 11, 2020
Published to the GitHub Advisory Database Nov 11, 2020
Published by the National Vulnerability Database Nov 11, 2020
Last updated Jan 31, 2023

Severity

High

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
Low
Privileges required
Low
User interaction
Required
Scope
Changed
Confidentiality
High
Integrity
High
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:L/PR:L/UI:R/S:C/C:H/I:H/A:N

EPSS score

0.081%
(35th percentile)

Weaknesses

CVE ID

CVE-2020-15275

GHSA ID

GHSA-4q96-6xhq-ff43

Source code

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