# CVE-2026-42875: External Secrets Operator namespace isolation bypass in CAProvider ConfigMap

Source: https://junglewise.ai/threats/cve-2026-42875-external-secrets-operator-namespace-isolation-bypass-in  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-05-11. Updated: 2026-05-13  
License: CC BY 4.0 with a link back

CVE-2026-42875 · Severity: medium · CVSS 4 · Published 2026-05-11

External Secrets Operator is a Kubernetes tool that integrates third-party secret management services like AWS Secrets Manager into Kubernetes. A vulnerability was found where a user in one project (namespace) could access security certificates belonging to another project. While this does not directly expose sensitive passwords, it allows unauthorized users to verify the existence of resources in other projects and potentially interfere with secure connections.

Technologies: [External Secrets Operator](https://junglewise.ai/threats/technologies/external-secrets-operator), [github.com/external-secrets/external-secrets (Go)](https://junglewise.ai/threats/technologies/github-com-external-secrets-external-secrets). Vendors: [External Secrets Operator](https://junglewise.ai/threats/vendors/external-secrets-operator), [Go](https://junglewise.ai/threats/vendors/go).

## Quick answers

**Is CVE-2026-42875 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-42875 being exploited in the wild.

**How severe is CVE-2026-42875?** Medium severity, with a CVSS score of 4, published 11 May 2026.

**Which products and versions are affected?** External Secrets Operator < 2.4.0; github.com/external-secrets/external-secrets (Go) < 2.4.0, SEMVER:introduced=0, SEMVER:introduced=0,fixed=2.4.0.

**Is there a fix for CVE-2026-42875?** Yes. github.com/external-secrets/external-secrets (Go): upgrade to 2.4.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-42875 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-42875?** Check whether you run External Secrets Operator or github.com/external-secrets/external-secrets (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- github.com/external-secrets/external-secrets (Go): upgrade to 2.4.0 or later

  ```sh
  go get github.com/external-secrets/external-secrets@v2.4.0
  ```


## Technical details

A namespace isolation bypass exists in External Secrets Operator when using CAProvider with type ConfigMap. Namespaced SecretStore resources could resolve CA material from a different namespace if the caProvider.namespace field was explicitly set, bypassing the intended security boundary enforced by the shared runtime CA resolver. An attacker with low privileges can exploit this to infer the existence of ConfigMaps or keys in other namespaces or force a SecretStore to consume unauthorized CA material. The vulnerability is patched in version 2.4.0.

## Affected products

- external-secrets external-secrets < 2.4.0

## Identifiers

- CVE-2026-42875
- GHSA-wv26-88m5-6h59
- GO-2026-5723

## Timeline

- 2026-04-24: disclosed: Vulnerability reported by moolen
- 2026-05-05: advisory: GitHub Advisory published
- 2026-05-11: other: NVD publication date

## References

- [https://api.github.com/users/moolen](https://api.github.com/users/moolen)
- [https://github.com/moolen](https://github.com/moolen)
- [https://api.github.com/users/moolen/gists%7B/gist_id%7D](https://api.github.com/users/moolen/gists%7B/gist_id%7D)
- [https://api.github.com/users/moolen/repos](https://api.github.com/users/moolen/repos)
- [https://avatars.githubusercontent.com/u/1709030?v=4](https://avatars.githubusercontent.com/u/1709030?v=4)
- [https://api.github.com/users/moolen/events%7B/privacy%7D](https://api.github.com/users/moolen/events%7B/privacy%7D)

## Related threats

- [External Secrets Operator label enforcement bypass in webhook generator](https://junglewise.ai/threats/cve-2026-26287-external-secrets-operator-label-enforcement-bypass-in-webhook)
- [External Secrets Operator privilege escalation via Service Account token injection](https://junglewise.ai/threats/cve-2026-42876-external-secrets-operator-privilege-escalation-via-service)
- [External Secrets Operator has DNS-based secret exfiltration via getHostByName in External Secrets v2 template engine](https://junglewise.ai/threats/cve-2026-34984-external-secrets-operator-has-dns-based-secret-exfiltration-via)
- [External Secrets Operator authorization bypass in getSecretKey function](https://junglewise.ai/threats/cve-2026-22822-external-secrets-operator-authorization-bypass-in-getsecretkey)
- [External Secrets Operator's Missing Namespace Restriction Allows Unauthorized Secret Access](https://junglewise.ai/threats/cve-2025-55196-external-secrets-operator-s-missing-namespace-restriction-allows)