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🛡️ CVE-2023-28120 — activesupport

🟡 CVSS 5.3 — Medium ✅ No Known Exploit CWE-79 NVD
5.3
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

Possible XSS Security Vulnerability in SafeBuffer#bytesplice

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.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity low, availability none.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

  • Attack vector: Network — reachable from anywhere that can route to the service.
  • Attack complexity: Low — the attack works reliably, with no preparation.
  • Privileges required: None — an unauthenticated stranger can try it.
  • User interaction: None — nobody has to be tricked into anything.
  • Scope: Unchanged — the damage stays inside the vulnerable component.
  • Confidentiality impact: None.
  • Integrity impact: Low — limited, and the attacker does not choose what is affected.
  • Availability impact: None.

Weakness class

CVE-2023-28120 is classified as CWE-79: Cross-site Scripting (XSS). User-supplied data is written into a page without escaping, so attacker script runs in the browser of anyone who views it.

Affected software

CVE-2023-28120 is recorded against 2 packages.

  • activesupport (fixed in 6.1.7.3)
  • unknown

Timeline and source

Published on 15 March 2023 and last revised on 10 January 2025. No public exploit is currently recorded for this entry. Record sourced from NVD.

References

nvd.nist.gov (Advisory)
github.com (Web)
discuss.rubyonrails.org (Web)
github.com (Web)
lists.fedoraproject.org (Web)
lists.fedoraproject.org (Web)
security.netapp.com (Web)
www.debian.org (Web)

Other advisories for this package

activesupport has other advisories on record. If you are patching this one, these are worth checking on the same host:

Same weakness in other software

These advisories are the same class of weakness (CWE-79: Cross-site Scripting (XSS)) in other software:

CVE-2023-28120 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity Medium
CVSS Score 5.3
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
CWE CWE-79
Public Exploit ✅ No
Source NVD
Published 2023-03-15
Updated 2026-08-20
Modified 2025-01-10
Fix URL N/A

Affected Packages

Software From version Fixed in
activesupport — 6.1.7.3
unknown — —

Similar Threats

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ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.

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