# CVE-2026-42875: External Secrets Operator: Namespace Isolation Bypass in CAProvider ConfigMap Resolution for SecretStore

> Attackers can bypass namespace isolation to read CA material from other namespaces via misconfigured SecretStore resources in External Secrets Operator.

- **Severity:** Medium 5.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 11 May 2026
- **Updated:** 12 May 2026
- **Also known as:** GHSA-wv26-88m5-6h59, GO-2026-5723, MINI-q32v-cmmw-6hmq, MINI-rvw6-j2q5-qc8f

## What is CVE-2026-42875?

CVE-2026-42875 is a medium-severity missing authorization vulnerability in external-secrets, published on 11 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

External Secrets Operator reads information from a third-party service and automatically injects the values as Kubernetes Secrets. Prior to 2.4.0, Namespaced SecretStore resources that used CAProvider with type ConfigMap could resolve CA material from another namespace when caProvider.namespace was set. This bypassed the namespace boundary enforced for SecretStore-backed references in providers that rely on the shared runtime CA resolver. This vulnerability is fixed in 2.4.0.

Weakness: CWE-668 (Exposure of Resource to Wrong Sphere), CWE-285 (Improper Authorization)

## Which versions are affected by CVE-2026-42875?

3 open source packages ship an affected version, including github.com/external-secrets/external-secrets.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/external-secrets/external-secrets` | Go | All versions | None |
| `github.com/external-secrets/external-secrets` | Go | All versions | 2.4.0 |
| `github.com/external-secrets/external-secrets` | Go | All versions | 2.4.0 |

## How do I fix CVE-2026-42875?

Upgrade github.com/external-secrets/external-secrets to 2.4.0 or later.

## Is CVE-2026-42875 being exploited?

There is no known exploitation of CVE-2026-42875 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-42875 and fix it if it is affected.

What it is: CVE-2026-42875 is a medium-severity missing authorization vulnerability in external-secrets, published on 11 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-42875 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/external-secrets/external-secrets (Go): affected all versions; no fix listed
- github.com/external-secrets/external-secrets (Go): affected all versions; fixed in 2.4.0
- github.com/external-secrets/external-secrets (Go): affected all versions; fixed in 2.4.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-42875/ (Markdown: https://insights.sbomify.com/CVE-2026-42875/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-42875
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-42875
- OSV: https://osv.dev/vulnerability/CVE-2026-42875

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-42875/
Summaries are generated and may contain mistakes; the official description above is the record.