CVE-2026-10052: Quay SSRF in LDAP/SMTP Validation—Internal Network Reconnaissance Risk

Technical summary

CVE-2026-10052 is a Server-Side Request Forgery (SSRF) vulnerability in Quay's config-tool affecting LDAP and SMTP validation logic. The flaw stems from improper input validation on user-supplied endpoints; the validation functions initiate outbound connections without enforcing IP address allowlists or hostname filtering, enabling a privileged attacker to conduct internal network reconnaissance. The attack surface is scoped to users with config editor access, limiting the immediate threat model but creating lateral movement and reconnaissance opportunities for insider threats or post-exploitation scenarios where config access has been compromised.

Business impact

For organizations running Quay as a container registry, this vulnerability enables internal network mapping by a config editor. In a compromised state or through insider threat, an attacker gains visibility into internal services, databases, and infrastructure previously unknown. This reconnaissance can precede more targeted attacks on identified systems. The CVSS score of 4.1 (Medium) reflects the requirement for high-privilege access, but the confidentiality impact is material—an attacker learns the topology and presence of internal systems without triggering typical network monitoring.

Affected systems

This vulnerability affects Quay instances where users have been granted configuration editor permissions. The impact is localized to the pod or container running Quay's config-tool; reconnaissance is performed from the Quay container's network namespace, meaning the attacker can reach hosts and services accessible from that vantage point. No specific version range is provided in the advisory; verify the affected versions and patch availability against the vendor's security advisory.

Exploitability

Exploitation requires config editor privileges, which is a moderately high barrier for external attackers but a realistic threat for insider scenarios or post-compromise situations where an attacker has gained admin or editor-level access to Quay. No active exploitation has been reported in the wild (KEV status: not listed). The attack is straightforward to execute once privileges are obtained: an attacker simply supplies attacker-controlled endpoints to LDAP or SMTP validation functions and observes responses or timing to infer the presence of internal services. No special tools or complex techniques are required.

Remediation

Patch Quay to the latest version addressing CVE-2026-10052; consult the vendor advisory for the specific patched version. The fix should implement proper input validation and IP/hostname filtering on LDAP and SMTP endpoints, potentially including an allowlist of permitted internal ranges or a deny-by-default policy. As an interim control, restrict config editor access to trusted personnel and implement network policies (e.g., egress rules) preventing the Quay pod from reaching unexpected internal services.

Patch guidance

Obtain the latest patched version from Red Hat/Quay's official release channels. Before deployment, test in a non-production environment to confirm LDAP and SMTP validation still functions correctly. Apply the patch to all Quay instances that permit configuration editing, prioritizing production systems first. Verify that post-patch, LDAP and SMTP settings continue to resolve and validate properly against legitimate endpoints.

Detection guidance

Monitor Quay pod egress traffic for unexpected connections to internal services during config validation. Audit Quay's configuration change logs for modifications to LDAP or SMTP endpoints, especially entries pointing to private IP ranges or unusual internal hostnames. In container runtime logs or network policies, alert on outbound connections from Quay pods to internal resources that were not explicitly configured. Watch for repeated failed connection attempts from the Quay pod to different internal hosts, which may indicate reconnaissance scanning.

Why prioritize this

Although the CVSS score is Medium (4.1), prioritization should account for your organization's insider threat model and the sensitivity of internal network topology. If your config editor role is tightly controlled and audited, risk is lower. If multiple users hold this role or if container compromise is a realistic threat model, prioritize patching higher. The vulnerability enables reconnaissance with minimal noise, making it attractive to sophisticated attackers seeking to map infrastructure before a more damaging attack.

Risk score, explained

The CVSS 3.1 score of 4.1 reflects a Medium severity because the attack vector is network-based but the attack complexity is low and the privilege requirement is high. The scope is changed (S:C) because the attacker, operating from within Quay, can learn about resources beyond the application's intended boundary. The impact is confidentiality only (C:L) with no integrity or availability impact, as the attacker gains information without modifying systems or causing downtime. The score appropriately captures that this is an information disclosure risk requiring valid credentials, not a full compromise vector.

Frequently asked questions