avo possible unsafe reflection / partial DoS vulnerability

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

8.3 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:H

EPSS

• CVE-2023-34102: 1.61% estimated exploitation activity in the next 30 days; percentile 75.97 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary The polymorphic field type stores the classes to operate on when updating a record with user input, and does not validate them in the back end. This can lead to unexpected behavior, remote code execution, or application crashes when viewing a manipulated record. Details After reviewing the polymorphic field implementation and performing some black box approaches, we identified a potential security issue related to the use of safeconstantize / constantize. This Rails functionality is capable of searching for classes within the Rails context and returning the class for further use. Because Avo does not validate user input when updating or creating a new polymorphic resource, it is possible to create database entries with completely different or invalid class names than the preselected ones. Avo assumes that the class specified by the user request is a valid one and attempts to work with it, which may result in dangerous behavior and code execution. PoC In the test scenario we…

Published by the source

6 Jun 2023, 16:46 UTC

Last modified by the source

25 Jun 2024, 16:56 UTC

Source last checked

26 Oct 2026, 15:48 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-86h2-2g4g-29qx

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# Patch Next advisory brief: CVE-2023-34102

Advisory: avo possible unsafe reflection / partial DoS vulnerability
IDs: CVE-2023-34102, GHSA-86h2-2g4g-29qx
Record: https://patchnext.com/advisories/cve-2023-34102 (revision 1, source checked 26 Oct 2026, 15:48 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Partial vendor fix; fixed versions by package: avo 2.33.3. A vendor fix does not mean a deployment is fixed.

## Affected components
- RubyGems avo: affected <= 2.33.2; >= 3.0.0.pre1, <= 3.0.0.pre12; fixed in 2.33.3

## Suggested inspection (read-only)
- RubyGems avo: check the installed version with your package manager.

## Supported action
No complete vendor fix is recorded. Follow the primary source's mitigation guidance and check this record again before closing anything.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on avo.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-86h2-2g4g-29qx (GitHub-reviewed advisory GHSA-86h2-2g4g-29qx lists affected ranges: RubyGems avo >=0 =3.0.0.pre1 <=3.0.0.pre12)

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