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HIGH

CVE-2026-54330

CVSS v3

8.1

HIGH

EPSS Score

0.4 %

exploit probability, as of 2026-10-19

CISA KEV

No

known exploited

Exploitation

—

SSVC status

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Affected and fixed versions

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • cephBitnamifrom 19.0.0 · fixed in 19.2.6

Vendor advisories

  • CVE-2026-54330 Red Hat Product Security225 products fixed · 166 known affected

    ceph: ceph: RGW SigV4 verifier allows attachment of arbitrary unsigned x-amz-* headers leading to privilege escalation

    ceph-base as a component of Red Hat Ceph Storage 4 · ceph-common as a component of Red Hat Ceph Storage 4 · ceph-fuse as a component of Red Hat Ceph Storage 4

  • RHSA-2026:79243 Red Hat Product Security4 products fixed

    Red Hat Security Advisory: Red Hat Ceph Storage

  • RHSA-2026:79101 Red Hat Product Security221 products fixed

    Red Hat Security Advisory: Red Hat Ceph Storage 8.1 security and bug fix updates

Full record on NVD

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.

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Published
2026-08-28
Last Modified
2026-08-28

Frequently asked questions

What is CVE-2026-54330?

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.

Is CVE-2026-54330 actively exploited?

Active exploitation of CVE-2026-54330 has not been confirmed. Its EPSS score was 0.4% on 2026-10-19, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-54330?

CVE-2026-54330 has a CVSS v3 base score of 8.1 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N.

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