CVE-2026-10052: Quay Config-Tool SSRF Vulnerability

CVE-2026-10052 Overview

CVE-2026-10052 is a Server-Side Request Forgery (SSRF) vulnerability in the Red Hat Quay config-tool. The flaw resides in the Lightweight Directory Access Protocol (LDAP) and Simple Mail Transfer Protocol (SMTP) validation functions. These functions accept user-supplied endpoints and make outbound network connections without filtering target IP addresses or hostnames. An attacker holding config editor privileges can abuse these handlers to probe internal network resources from the Quay pod's network position. The flaw is tracked under CWE-918: Server-Side Request Forgery.

Critical Impact
Authenticated config editors can use Quay validation endpoints as an internal scanning proxy, enabling reconnaissance of services reachable from the Quay pod inside Kubernetes or OpenShift clusters.

Affected Products

Red Hat Quay config-tool component
Quay registry deployments exposing the configuration editor interface
Containerized Quay installations on OpenShift and Kubernetes

Discovery Timeline

2026-05-29 - CVE CVE-2026-10052 published to NVD
2026-05-29 - Last updated in NVD database

Technical Details for CVE-2026-10052

Vulnerability Analysis

The Quay config-tool exposes validation endpoints that test administrator-supplied LDAP and SMTP configuration values. When an operator enters a host and port for either protocol, the tool initiates an outbound connection to confirm reachability before saving the configuration. The validators trust the supplied destination and skip allowlist checks, hostname resolution checks, and private-network filtering.

An authenticated user with config editor access can supply arbitrary internal IP addresses or hostnames. The Quay pod then attempts connections on the attacker's behalf. Response timing, error messages, and connection success/failure leak information about reachable hosts, open ports, and internal service banners. This converts the configuration validator into an internal port scanner.

The attack vector is network-based and requires high privileges, but the scope is changed because Quay reaches resources outside its own security boundary, including kubelet APIs, cloud metadata services, and adjacent workloads.

Root Cause

The root cause is missing input validation on user-controlled network destinations in the LDAP and SMTP validation routines. The code does not enforce an allowlist of permitted hosts. It does not block link-local, loopback, or RFC1918 ranges. It does not restrict ports. CWE-918 captures this class of SSRF defect where a server fetches a remote resource without validating the user-supplied URL or endpoint.

Attack Vector

The attacker must first obtain config editor credentials for the Quay deployment. Using the configuration user interface or its underlying API, the attacker submits an LDAP or SMTP validation request pointing at an internal target such as 169.254.169.254 (cloud metadata) or a Kubernetes service IP. The Quay pod connects to the target and returns timing or error data. The attacker iterates across IP ranges and ports to map internal infrastructure. No code execution or data exfiltration from Quay itself is required for reconnaissance, though discovered services may be attacked through other means.

No verified public exploit code is available. See the Red Hat CVE-2026-10052 Advisory and Red Hat Bug Report #2483157 for vendor technical details.

Detection Methods for CVE-2026-10052

Indicators of Compromise

Repeated calls to Quay config-tool LDAP or SMTP validation endpoints from a single authenticated session
Outbound TCP connections from the Quay pod targeting RFC1918 ranges, link-local addresses, or cloud metadata IPs such as 169.254.169.254
Validation requests containing internal hostnames that do not match documented LDAP or SMTP infrastructure
Unusual port numbers supplied in LDAP or SMTP host fields, indicating scanning rather than legitimate configuration

Detection Strategies

Audit Quay configuration API logs for sequential validation attempts that vary only by IP address or port
Correlate config editor session activity with egress connection logs from the Quay pod
Apply network policy telemetry to flag Quay pod connections to non-approved internal destinations
Alert on Quay validation endpoint usage outside of change windows or by non-administrator service accounts

Monitoring Recommendations

Enable Kubernetes audit logging for Quay namespaces and forward to a centralized analytics platform
Capture pod-level egress flows using a service mesh, CNI plugin, or eBPF-based sensor
Track authentication events for config editor role assignments and changes
Review Quay application logs for ldap_validator and smtp_validator invocations and their target arguments

How to Mitigate CVE-2026-10052

Immediate Actions Required

Restrict the config editor role to a minimal set of trusted administrators and rotate credentials for existing holders
Apply Kubernetes NetworkPolicy resources that deny Quay pod egress to internal management ranges and cloud metadata endpoints
Disable or proxy access to the Quay configuration UI when active configuration changes are not in progress
Monitor Red Hat advisories for the patched config-tool build and schedule deployment

Patch Information

Red Hat tracks the fix under Red Hat Bug Report #2483157. Consult the Red Hat CVE-2026-10052 Advisory for affected Quay versions and the corresponding patched releases. Upgrade Quay to the fixed version once available and redeploy the operator-managed components.

Workarounds

Place the Quay configuration editor behind an authenticating reverse proxy with strict IP allowlists
Apply egress firewall rules at the cluster boundary to block Quay pods from reaching internal subnets unrelated to its operation
Block access to instance metadata services from Quay pods using a hop-limit filter or explicit deny rule
Remove the config editor role from accounts that do not require it and audit role assignments regularly

bash

# Example Kubernetes NetworkPolicy restricting Quay pod egress
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: quay-egress-restrict
  namespace: quay-enterprise
spec:
  podSelector:
    matchLabels:
      app: quay
  policyTypes:
    - Egress
  egress:
    - to:
        - ipBlock:
            cidr: 0.0.0.0/0
            except:
              - 169.254.0.0/16
              - 10.0.0.0/8
              - 172.16.0.0/12
              - 192.168.0.0/16