Avo: Direct attachment upload endpoint lacks upload authorization and bypasses field-level upload policy

Exploitation

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

CVSS

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

EPSS

• CVE-2026-53769: 0.42% estimated exploitation activity in the next 30 days; percentile 36.64 (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 Avo's direct attachment upload endpoint lacks server-side upload authorization and bypasses the documented field-level upload policy methods such as upload{FIELDID}?. An authenticated Avo user who can reach the Avo attachment upload endpoint can replace or add attachment content, including binary content, filename, and content-type metadata, on a resolved record even when both update? and upload<field? policies deny the operation. This primarily affects multi-role Avo Pro/Advanced-style deployments where non-administrator or restricted operator users can reach Avo and per-record or per-field operations are expected to be enforced by policies. Details Avo exposes a direct attachment upload endpoint: The vulnerable code path is Avo::AttachmentsController#create: - app/controllers/avo/attachmentscontroller.rb:9-24 Current behavior: This endpoint creates an ActiveStorage::Blob before validating the requested attachment association and before any upload authorization could be…

Published by the source

9 Jul 2026, 20:54 UTC

Last modified by the source

9 Jul 2026, 20:54 UTC

Source last checked

26 Oct 2026, 15:52 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-pqpw-cvm4-8mv9

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# Patch Next advisory brief: CVE-2026-53769

Advisory: Avo: Direct attachment upload endpoint lacks upload authorization and bypasses field-level upload policy
IDs: CVE-2026-53769, GHSA-pqpw-cvm4-8mv9
Record: https://patchnext.com/advisories/cve-2026-53769 (revision 1, source checked 26 Oct 2026, 15:52 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: avo 3.32.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- RubyGems avo: affected >= 2.28.0, < 3.32.0; fixed in 3.32.0

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

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## 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-pqpw-cvm4-8mv9 (GitHub-reviewed advisory GHSA-pqpw-cvm4-8mv9 lists affected ranges: RubyGems avo >=2.28.0 <3.32.0)

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