CVE-2026-54659 ddnexus CVE debrief

Who should care

Defenders who use the Pagy gem in their Ruby applications should be aware of this vulnerability and take steps to upgrade to version 43.5.6 or later. They should review and update affected systems, monitor for potential attacks, and verify if their systems are affected. Defenders should also prioritize upgrading to the fixed version to prevent potential attacks.

Why it matters

CVE-2026-54659 is a vulnerability in the Pagy gem that allows attackers to read arbitrary YAML files. Defenders should prioritize upgrading to version 43.5.6 or later to prevent potential attacks.

• Attackers may be able to read sensitive information from YAML files
• Defenders need to verify if their systems are affected and upgrade to a fixed version
• The vulnerability requires authentication but has a high CVSS score due to its potential impact

Technical summary

The Pagy gem is vulnerable to a file existence and readability oracle attack due to its handling of locale values. An attacker can provide a specially crafted locale value to read arbitrary YAML files. The issue arises from the Pagy::I18n.locale= method storing locale values verbatim and using them as <locale>.yml path components. The vulnerability is fixed in version 43.5.6. Defenders should prioritize upgrading to the fixed version to prevent potential attacks. The vulnerability has a CVSS score of 6.9 and is considered MEDIUM severity.

Defensive priority

Defenders should prioritize upgrading to version 43.5.6 or later to prevent potential attacks.

Recommended defensive actions

• Upgrade to version 43.5.6 or later
• Review and update affected systems
• Monitor for potential attacks
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up.
• Review compensating controls for exposed systems while remediation is scheduled and verified.
• Check relevant monitoring, detection, and logs for exposed assets that need extra review.
• Track exceptions, retest remediated assets, and close the item only after evidence is documented.

Evidence notes

The vulnerability is caused by the Pagy::I18n.locale= method storing locale values verbatim and later using them as <locale>.yml path components. This allows an attacker to provide a specially crafted locale value to read arbitrary YAML files. The issue is fixed in version 43.5.6. The CVE record was published on 2026-07-28T23:17:09.067Z and has not been modified since then. The vulnerability has a CVSS score of 6.9 and is considered MEDIUM severity.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.