CVE 2026 94368

A flaw was found in the signature verification logic of noobaa-core, the core component of the NooBaa Multicloud Object Gateway. The issue occurs when the service processes S3 presigned URLs using Signature Version 4 (SigV4). Due to improper validation, the service fails to reject requests containing unsigned x-amz- headers, instead simply dropping them from the signature calculation. This allows an attacker who possesses a valid presigned PUT URL to add an unsigned x-amz-copy-source header, effectively converting a simple upload into a CopyObject operation. This can lead to unauthorized access and copying of any data the original signer is permitted to reach across the entire storage system.

The Red Hat Product Security team has assessed the severity of this vulnerability as Important, given that an attacker only needs a valid presigned URL to exploit the flaw. Successful exploitation allows an attacker to bypass intended access controls to read or overwrite any data accessible to the signer of the URL. The vulnerability's root cause is a failure to enforce that all x-amz- headers in a SigV4 request are included in the cryptographic signature.

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.

Bugzilla 2537364 : noobaa-core: noobaa-core: Presigned PUT URL escalation to CopyObject via unsigned x-amz-copy-source header

CWE-347 : Improper Verification of Cryptographic Signature

Common Vulnerability Scoring System (CVSS) Score Details

Info alert: Important note

CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications ).

The following CVSS metrics and score provided are preliminary and subject to review.

CVSS v3 Score Breakdown

Red Hat: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N

Understanding the Weakness (CWE)

Access Control,Integrity,Confidentiality

Technical Impact: Gain Privileges or Assume Identity; Modify Application Data; Execute Unauthorized Code or Commands

An attacker could gain access to sensitive data and possibly execute unauthorized code.

Red Hat would like to thank Oren Yomtov (act.security) for reporting this issue.

Frequently Asked Questions

"Under investigation" doesn't necessarily mean that the product is affected by this vulnerability. It only means that our Analysis Team is still working on determining whether the product is affected and how it is affected.

The term 'Affected' means that our Analysis team has determined that this product, such as Red Hat Enterprise Linux 8 or OpenShift Container Platform 4, is affected by this vulnerability and a fix may be released to address this issue in the near future. This includes all minor releases of this product unless noted otherwise in the Statement text.

Upgrade to a supported product version that includes a fix for this vulnerability (recommended).

Apply a mitigation (if one exists).

Customers with the Technical Account Manager (TAM) RHEL Security Select Add-on can review this CVE directly with their TAM.

Apply a mitigation (if one exists).

Red Hat Engineering focuses on addressing high-priority issues based on the impact and product lifecycle expectations. Therefore, lower-priority issues will not receive immediate fixes.

Customers with the technical account manager (TAM) RHEL Security Select Add-on can review this CVE directly with their TAM.

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