# CVE-2026-54330: Ceph RGW SigV4 handler accepts unsigned x-amz-* headers on presigned requests, allowing privilege escalation

> Attackers can escalate privileges by adding unsigned headers to presigned URLs in Ceph RGW, bypassing intended access controls.

- **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/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:** 27 Aug 2026
- **Updated:** 1 Sep 2026
- **Also known as:** AZL-98340, BIT-ceph-2026-54330, DEBIAN-CVE-2026-54330, ECHO-ba60-36e6-9bcf, GHSA-rmjq-ffrm-j6vj, MINI-f5cf-gmhp-52ch, MINI-gm7c-rf8m-pf63, UBUNTU-CVE-2026-54330, USN-8867-1

## What is CVE-2026-54330?

CVE-2026-54330 is a high-severity authentication bypass vulnerability in ceph, published on 27 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Ceph is an open-source distributed storage platform providing object, block, and file storage. In versions prior to 20.2.4 and 19.2.6, the Ceph Object Gateway (RGW) SigV4 handler does not reject requests that carry x-amz-* headers absent from the signed header set, allowing anyone holding a presigned URL to attach arbitrary unsigned x-amz-* headers that RGW will honor. AWS S3 requires every x-amz-* header on a SigV4 request to be signed and rejects requests bearing additional unsigned headers, but RGW validates only the headers listed in X-Amz-SignedHeaders and ignores any extra ones, so they take effect without being covered by the signature. By adding such headers to a presigned PUT URL, an attacker can grant themselves more capabilities than the URL's signer intended and escalate their privileges. This issue is fixed in versions 20.2.4 and 19.2.6.

Weakness: CWE-347 (Improper Verification of Cryptographic Signature)

## Which versions are affected by CVE-2026-54330?

1 open source package ship an affected version, including ceph.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `ceph` | Bitnami | From 19.0.0 | 19.2.6, 20.2.4 |

## How do I fix CVE-2026-54330?

Upgrade ceph to a fixed version for your release line: 19.2.6 or 20.2.4.

## Is CVE-2026-54330 being exploited?

There is no known exploitation of CVE-2026-54330 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-54330 and fix it if it is affected.

What it is: CVE-2026-54330 is a high-severity authentication bypass vulnerability in ceph, published on 27 Aug 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-2026-54330 in the wild and no public exploit code.

Affected packages and fixed versions:
- ceph (Bitnami): affected from 19.0.0; fixed in 19.2.6, 20.2.4

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-2026-54330/ (Markdown: https://insights.sbomify.com/CVE-2026-54330/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-54330
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-54330
- OSV: https://osv.dev/vulnerability/CVE-2026-54330

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-54330/
Summaries are generated and may contain mistakes; the official description above is the record.