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Possible XSS Security Vulnerability in SafeBuffer#bytesplice

Moderate severity GitHub Reviewed Published Mar 15, 2023 to the GitHub Advisory Database • Updated Jan 10, 2025

Package

bundler activesupport (RubyGems)

Affected versions

>= 7.0.0, < 7.0.4.3
< 6.1.7.3

Patched versions

7.0.4.3
6.1.7.3

Description

There is a vulnerability in ActiveSupport if the new bytesplice method is called on a SafeBuffer with untrusted user input.
This vulnerability has been assigned the CVE identifier CVE-2023-28120.

Versions Affected: All. Not affected: None Fixed Versions: 7.0.4.3, 6.1.7.3

Impact

ActiveSupport uses the SafeBuffer string subclass to tag strings as html_safe after they have been sanitized.
When these strings are mutated, the tag is should be removed to mark them as no longer being html_safe.

Ruby 3.2 introduced a new bytesplice method which ActiveSupport did not yet understand to be a mutation.
Users on older versions of Ruby are likely unaffected.

All users running an affected release and using bytesplice should either upgrade or use one of the workarounds immediately.

Workarounds

Avoid calling bytesplice on a SafeBuffer (html_safe) string with untrusted user input.

References

Published to the GitHub Advisory Database Mar 15, 2023
Reviewed Mar 15, 2023
Published by the National Vulnerability Database Jan 9, 2025
Last updated Jan 10, 2025

Severity

Moderate

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
None
User interaction
None
Scope
Unchanged
Confidentiality
None
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:L/PR:N/UI:N/S:U/C:N/I:L/A:N

EPSS score

0.044%
(12th percentile)

Weaknesses

CVE ID

CVE-2023-28120

GHSA ID

GHSA-pj73-v5mw-pm9j

Source code

No known source code
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