# CVE-2026-54247: Skipper: Unbounded Request Body Read in Admission Webhook Causes Memory Exhaustion DoS

> An attacker with in-cluster access can cause memory exhaustion and process termination in Skipper by sending large request bodies to the admission webhook.

- **Severity:** Medium 4.3 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L`)
- **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:** 14 Sep 2026
- **Updated:** 16 Sep 2026
- **Also known as:** GHSA-cwxq-rc9x-2jvv, GO-2026-6015

## What is CVE-2026-54247?

CVE-2026-54247 is a medium-severity denial of service vulnerability in zalando skipper, published on 14 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Skipper is an HTTP router and reverse proxy for service composition. Prior to 0.26.22, Handler in dataclients/kubernetes/admission/admission.go passes the body of requests to the Kubernetes admission endpoint at :9443/admission directly to io.ReadAll(r.Body) without a size limit. An attacker with in-cluster network access and a valid Kubernetes client certificate can send a very large body that causes unbounded memory allocation and an out-of-memory termination of the Skipper process. The disruption is limited to Ingress and RouteGroup admission rather than pod creation or unrelated admission controllers, and Kubernetes normally restarts the process. This issue is fixed in version 0.26.22.

Weakness: CWE-770 (Allocation of Resources Without Limits or Throttling)

## Which versions are affected by CVE-2026-54247?

3 open source packages ship an affected version, including github.com/zalando/skipper.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/zalando/skipper` | Go | All versions | 0.26.22 |
| `github.com/zalando/skipper` | Go | All versions | 0.26.22 |
| `github.com/zalando/skipper` | Go | All versions | 0.26.22 |

## How do I fix CVE-2026-54247?

Upgrade github.com/zalando/skipper to 0.26.22 or later.

## Is CVE-2026-54247 being exploited?

There is no known exploitation of CVE-2026-54247 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-54247 and fix it if it is affected.

What it is: CVE-2026-54247 is a medium-severity denial of service vulnerability in zalando skipper, published on 14 Sep 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-2026-54247 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/zalando/skipper (Go): affected all versions; fixed in 0.26.22
- github.com/zalando/skipper (Go): affected all versions; fixed in 0.26.22
- github.com/zalando/skipper (Go): affected all versions; fixed in 0.26.22

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-2026-54247/ (Markdown: https://insights.sbomify.com/CVE-2026-54247/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-54247
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-54247
- OSV: https://osv.dev/vulnerability/CVE-2026-54247

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-54247/
Summaries are generated and may contain mistakes; the official description above is the record.