# CVE-2025-66564

## Summary

- **CVE ID:** CVE-2025-66564
- **Severity:** HIGH
- **CVSS Score:** 7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
- **CWE:** CWE-405
- **Published:** Dec 4, 2025
- **Last Modified:** Mar 13, 2026

## Description

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.

## Affected Products

- sigstore — timestamp-authority (< 2.0.3)

## References

- [CNA](https://github.com/sigstore/timestamp-authority/security/advisories/GHSA-4qg8-fj49-pxjh)
- [CNA](https://github.com/sigstore/timestamp-authority/commit/0cae34e197d685a14904e0bad135b89d13b69421)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.44%
- **EPSS Percentile:** 37.3

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-11._