CVE-2025-24976 in Distribution
Summary
by MITRE • 02/11/2025
Distribution is a toolkit to pack, ship, store, and deliver container content. Systems running registry versions 3.0.0-beta.1 through 3.0.0-rc.2 with token authentication enabled may be vulnerable to an issue in which token authentication allows an attacker to inject an untrusted signing key in a JSON web token (JWT). The issue lies in how the JSON web key (JWK) verification is performed. When a JWT contains a JWK header without a certificate chain, the code only checks if the KeyID (`kid`) matches one of the trusted keys, but doesn't verify that the actual key material matches. A fix for the issue is available at commit 5ea9aa028db65ca5665f6af2c20ecf9dc34e5fcd and expected to be a part of version 3.0.0-rc.3. There is no way to work around this issue without patching if the system requires token authentication.
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Analysis
by VulDB Data Team • 01/23/2026
The vulnerability described in CVE-2025-24976 affects the distribution toolkit version 3.0.0-beta.1 through 3.0.0-rc.2 when token authentication is enabled. This represents a critical security flaw in the container registry's authentication mechanism that could allow attackers to bypass authentication controls and gain unauthorized access to container content. The issue specifically targets the JSON Web Token (JWT) validation process, which is fundamental to secure container image distribution and management. The vulnerability stems from improper verification of JSON Web Key (JWK) material during token authentication, creating a potential backdoor for malicious actors to manipulate authentication flows.
The technical flaw manifests in the insufficient validation of JWT headers when processing JSON web keys. When a JWT contains a JWK header without a certificate chain, the system performs only a superficial check to verify that the KeyID (kid) matches one of the trusted keys in the system. However, this validation process fails to confirm that the actual cryptographic key material corresponds to the expected trusted key. This creates a scenario where an attacker could inject an untrusted signing key into the JWT payload while maintaining the appearance of a valid authentication token. The vulnerability directly relates to CWE-347, which addresses improper verification of cryptographic signatures, and specifically targets the weakness in JWT validation that allows for key confusion attacks.
The operational impact of this vulnerability is significant for organizations relying on container registries for secure image distribution. Attackers exploiting this vulnerability could potentially bypass authentication mechanisms and gain access to container images, potentially leading to supply chain attacks, unauthorized code execution, or data breaches. The issue affects systems where token authentication is required, making it particularly dangerous for production environments where container security is paramount. Organizations using vulnerable versions of the distribution toolkit may be unknowingly exposing their container repositories to unauthorized access, especially in environments where container images contain sensitive or proprietary code.
The fix for this vulnerability involves implementing proper verification of the actual key material in addition to the KeyID matching. The patch referenced in commit 5ea9aa028db65ca5665f6af2c20ecf9dc34e5fcd addresses the core issue by ensuring that when a JWT contains a JWK header without a certificate chain, the system validates not just the KeyID but also confirms that the cryptographic key material matches the expected trusted key. This enhanced validation prevents attackers from injecting untrusted signing keys into the authentication process. Organizations should immediately upgrade to version 3.0.0-rc.3 or apply the patch to mitigate this vulnerability, as there are no viable workarounds available for systems that require token authentication. The fix aligns with ATT&CK technique T1550.001, which covers use of stolen credentials, by ensuring that authentication tokens cannot be forged or manipulated to gain unauthorized access to container repositories.