CVE-2026-110310
Description
A flaw was found in Amazon.Extensions.S3.Encryption. A remote authenticated user with read access to encrypted objects in an Amazon Simple Storage Service (S3) bucket can force a cryptographic downgrade by altering the padding scheme in an object's metadata to legacy PKCS#1 v1.5. By exploiting this padding oracle flaw, an attacker can recover the encryption key and decrypt stored objects, leading to information disclosure.
Statement
This vulnerability is rated as Moderate impact because exploitation requires pre-existing authenticated read access to target storage objects and relies on high-complexity padding oracle queries rather than a direct key compromise. Red Hat does not distribute this third-party client library within core Red Hat Enterprise Linux platforms, meaning standard enterprise installations remain unaffected by default. Exposure is limited to user-developed .NET applications hosted on Red Hat environments that explicitly bundle this encryption package.
Understanding the Weakness (CWE)
Confidentiality,Access Control,Availability
Technical Impact: Bypass Protection Mechanism; Gain Privileges or Assume Identity; Varies by Context
When security decisions such as authentication and authorization are made based on the values of these inputs, attackers can bypass the security of the product to access whatever is being protected. An attacker could change these inputs using customized clients or other attacks. This change might not be detected. The consequences will depend on the associated functionality, but they can range from granting additional privileges to untrusted users to bypassing important security checks. Ultimately, this weakness may lead to exposure or modification of sensitive data, system crash, or execution of arbitrary code.
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