sigstore timestamp-authority up to 2.0.2 amplification

Summaryinfo

A vulnerability identified as problematic has been detected in sigstore timestamp-authority up to 2.0.2. This affects an unknown part. Performing a manipulation results in amplification. This vulnerability was named CVE-2025-66564. The attack may be initiated remotely. There is no available exploit. You should upgrade the affected component.

Detailsinfo

A vulnerability classified as problematic has been found in sigstore timestamp-authority up to 2.0.2. This affects some unknown functionality. The manipulation with an unknown input leads to a amplification vulnerability. CWE is classifying the issue as CWE-405. The product does not properly control situations in which an adversary can cause the product to consume or produce excessive resources without requiring the adversary to invest equivalent work or otherwise prove authorization, i.e., the adversary's influence is "asymmetric." This is going to have an impact on availability. The summary by CVE is:

Sigstore Timestamp Authority is a service for issuing RFC 3161 timestamps. Prior to 2.0.3, Function api.ParseJSONRequest currently splits (via a call to strings.Split) an optionally-provided OID (which is untrusted data) on periods. Similarly, function api.getContentType splits the Content-Type header (which is also untrusted data) on an application string. As a result, in the face of a malicious request with either an excessively long OID in the payload containing many period characters or a malformed Content-Type header, a call to api.ParseJSONRequest or api.getContentType incurs allocations of O(n) bytes (where n stands for the length of the function's argument). This vulnerability is fixed in 2.0.3.

The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2025-66564 since 12/04/2025. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Neither technical details nor an exploit are publicly available. MITRE ATT&CK project uses the attack technique T1499 for this issue.

The vulnerability scanner Nessus provides a plugin with the ID 277673 (Linux Distros Unpatched Vulnerability : CVE-2025-66564), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 2.0.3 eliminates this vulnerability. Applying the patch 0cae34e197d685a14904e0bad135b89d13b69421 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (277673) and EUVD (EUVD-2025-201319). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Vendor

• sigstore

Name

• timestamp-authority

Version

• 2.0.0
• 2.0.1
• 2.0.2

License

• open-source

Website

• Product: https://github.com/sigstore/timestamp-authority/

CPE 2.3info

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CPE 2.2info

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If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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