# CVE-2026-42876: External Secrets Operator: Privilege escalation with secret overwriting

> Users with ExternalSecret creation permissions can impersonate service accounts by forcing the operator to create long-lived token secrets.

- **Severity:** Medium 4.9 (`CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:L/A: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:** 6 Oct 2026
- **Also known as:** GHSA-fq7h-9x26-6j22, GO-2026-5377, MINI-55jf-w96x-jj7q, MINI-gcw7-q39r-j8x4

## What is CVE-2026-42876?

CVE-2026-42876 is a medium-severity 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 2.4.1, a user who only has permission to create ExternalSecret resources can cause the operator to create a Secret that Kubernetes will automatically populate with a long-lived token for the specified service account. This effectively allows the user to impersonate any service account in the namespace without needing direct create permissions on TokenRequest or Secrets of that type. This vulnerability is fixed in 2.4.1.

Weakness: CWE-285 (Improper Authorization)

## Which versions are affected by CVE-2026-42876?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/external-secrets/external-secrets/apis` | Go | All versions | None |
| `github.com/external-secrets/external-secrets/apis` | Go | From 0.1.0 | 2.4.1 |
| `github.com/external-secrets/external-secrets/apis` | Go | From 0.1.0 | 2.4.1 |

## How do I fix CVE-2026-42876?

Upgrade github.com/external-secrets/external-secrets/apis to 2.4.1 or later.

## Is CVE-2026-42876 being exploited?

There is no known exploitation of CVE-2026-42876 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-42876 and fix it if it is affected.

What it is: CVE-2026-42876 is a medium-severity 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-2026-42876 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/external-secrets/external-secrets/apis (Go): affected all versions; no fix listed
- github.com/external-secrets/external-secrets/apis (Go): affected from 0.1.0; fixed in 2.4.1
- github.com/external-secrets/external-secrets/apis (Go): affected from 0.1.0; fixed in 2.4.1

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-2026-42876/ (Markdown: https://insights.sbomify.com/CVE-2026-42876/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-42876
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-42876
- OSV: https://osv.dev/vulnerability/CVE-2026-42876

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-42876/
Summaries are generated and may contain mistakes; the official description above is the record.