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Sigstore Timestamp Authority allocates excessive memory during request parsing

High severity GitHub Reviewed Published Dec 4, 2025 in sigstore/timestamp-authority • Updated Dec 5, 2025

Package

gomod github.com/sigstore/timestamp-authority (Go)

Affected versions

<= 2.0.2

Patched versions

2.0.3

Description

Impact

Excessive memory allocation

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). Relevant weakness: CWE-405: Asymmetric Resource Consumption (Amplification)

Patches

Upgrade to v2.0.3.

Workarounds

There are no workarounds with the service itself. If the service is behind a load balancer, configure the load balancer to reject excessively large requests.

References

@haydentherapper haydentherapper published to sigstore/timestamp-authority Dec 4, 2025
Published by the National Vulnerability Database Dec 4, 2025
Published to the GitHub Advisory Database Dec 5, 2025
Reviewed Dec 5, 2025
Last updated Dec 5, 2025

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS score

Exploit Prediction Scoring System (EPSS)

This score estimates the probability of this vulnerability being exploited within the next 30 days. Data provided by FIRST.
(12th percentile)

Weaknesses

Asymmetric Resource Consumption (Amplification)

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. Learn more on MITRE.

CVE ID

CVE-2025-66564

GHSA ID

GHSA-4qg8-fj49-pxjh

Source code

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