# CVE-2026-76827: Search-indexer: search-indexer: update/delete operations not scoped to caller's cluster (cross-tenant data tampering)

> Authenticated managed clusters can tamper with or delete other clusters' indexed search data due to missing ownership checks in write operations.

- **Severity:** Medium 6.8 (`CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:N/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 19 Aug 2026
- **Updated:** 5 Sep 2026
- **Also known as:** GHSA-4vrw-8fx2-pj82

## What is CVE-2026-76827?

CVE-2026-76827 is a medium-severity missing authorization vulnerability in Red Hat Advanced Cluster Management for Kubernetes 2.11, published on 19 Aug 2026. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

A flaw was found in search-indexer. This vulnerability allows a registered and authenticated managed cluster to tamper with or delete another cluster's indexed search data. This is possible because the delta-sync write paths in search-indexer do not properly restrict UPDATE/DELETE operations to data owned by the calling cluster. An attacker could exploit this by crafting specific user identifiers (UIDs) with a different cluster's prefix.

Weakness: CWE-693 (Protection Mechanism Failure)

## Which versions are affected by CVE-2026-76827?


## How do I fix CVE-2026-76827?

No fix has been published for CVE-2026-76827 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-76827 being exploited?

There is no known exploitation of CVE-2026-76827 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-76827 and fix it if it is affected.

What it is: CVE-2026-76827 is a medium-severity missing authorization vulnerability in Red Hat Advanced Cluster Management for Kubernetes 2.11, published on 19 Aug 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-76827 in the wild and no public exploit code.

Affected product: Red Hat Advanced Cluster Management for Kubernetes 2.11. No package-level version data is available, so check the vendor advisory linked from the reference page.

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-2026-76827/ (Markdown: https://insights.sbomify.com/CVE-2026-76827/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-76827
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-76827
- OSV: https://osv.dev/vulnerability/CVE-2026-76827

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-76827/
Summaries are generated and may contain mistakes; the official description above is the record.