Security readout for executives and security teams
Plain-English summary
A Kubernetes user who can create or change Ingress objects may abuse ingress-nginx annotations to steal the controller’s credentials. In the default configuration, those credentials can read all cluster secrets, turning limited Ingress access into broad secret exposure.
Executive priority
High priority for Kubernetes environments with delegated Ingress management. The business risk is credential theft leading to cluster secret disclosure, including application credentials. Prioritize validation and remediation before expanding tenant or developer access.
Technical view
CVE-2021-25746 is an ingress-nginx annotation directive injection issue. The CVE states that create/update access to Ingress objects in networking.k8s.io or extensions can be used to obtain ingress-nginx controller credentials. CVSS is 7.6 high, with low attack complexity and low privileges required.
Likely exposure
Clusters using Kubernetes ingress-nginx are most exposed when non-admin users, CI jobs, or tenants can create or update Ingress resources. Exposure is higher where the controller runs with default broad secret access. The source bundle does not specify exact affected versions.
Exploitation context
The bundle does not show CISA KEV listing or cited evidence of active exploitation. Exploitation requires Kubernetes access with permission to create or update Ingress objects; it is not described as unauthenticated internet exploitation.
Researcher notes
Evidence is strong for vulnerability impact and prerequisites, but incomplete for exact affected versions, fixed versions, and observed exploitation in the provided bundle. Avoid assuming all Kubernetes clusters are affected; focus on ingress-nginx deployments and RBAC paths to Ingress modification.
Mitigation direction
- Check current Kubernetes ingress-nginx vendor guidance for fixed versions and configuration changes.
- Restrict Ingress create/update permissions to trusted administrators and controlled automation.
- Review the ingress-nginx controller service account permissions to secrets.
- Prioritize remediation in shared, multi-tenant, or delegated Kubernetes environments.
Validation and detection
- Inventory clusters running Kubernetes ingress-nginx.
- Identify users, groups, and service accounts with Ingress create/update permissions.
- Check whether the controller credential can access secrets cluster-wide.
- Review existing Ingress annotations for unexpected or risky configuration changes.
- Confirm remediation against Kubernetes ingress-nginx advisory guidance.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
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ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-20: Exact CWE lookup
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Open ATT&CK lookupCredential and access behavior lookup
The CVE wording references authentication or credential exposure, so valid-account and credential-access review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupContainer behavior lookup
The affected technology mentions containers, so container-specific ATT&CK technique review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-25746 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 7.6 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:L
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:L2.84.7Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.6HighVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:L
Source materials
- CVE List V5 sourceCVE List V5
- https://groups.google.com/g/kubernetes-security-announce/c/hv2-SfdqcfQCVE reference · x_refsource_MISC
- https://github.com/kubernetes/ingress-nginx/issues/8503CVE reference · x_refsource_MISC
- https://security.netapp.com/advisory/ntap-20220609-0006/CVE reference · x_refsource_CONFIRM
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Input Validation
Improper Input Validation represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.