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go-tuf affected by client DoS via malformed server response

Moderate severity GitHub Reviewed Published Jan 20, 2026 in theupdateframework/go-tuf • Updated Jan 22, 2026

Package

gomod github.com/theupdateframework/go-tuf/v2 (Go)

Affected versions

< 2.3.1

Patched versions

2.3.1

Description

Security Disclosure: Client DoS via malformed server response

Summary

If the TUF repository (or any of its mirrors) returns invalid TUF metadata JSON (valid JSON but not well formed TUF metadata), the client will panic during parsing, causing a DoS. The panic happens before any signature is validated. This means that a compromised repository/mirror/cache can DoS clients without having access to any signing key.

Impact

Client crashes upon receiving and parsing malformed TUF metadata. This can cause long running services to enter an restart/crash loop.

Workarounds

None currently.

Affected code

The metadata.checkType function did not properly type assert the (untrusted) input causing it to panic on malformed data.

References

@kommendorkapten kommendorkapten published to theupdateframework/go-tuf Jan 20, 2026
Published to the GitHub Advisory Database Jan 21, 2026
Reviewed Jan 21, 2026
Published by the National Vulnerability Database Jan 22, 2026
Last updated Jan 22, 2026

Severity

Moderate

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
High
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:H/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.
(11th percentile)

Weaknesses

Reachable Assertion

The product contains an assert() or similar statement that can be triggered by an attacker, which leads to an application exit or other behavior that is more severe than necessary. Learn more on MITRE.

Improper Check for Unusual or Exceptional Conditions

The product does not check or incorrectly checks for unusual or exceptional conditions that are not expected to occur frequently during day to day operation of the product. Learn more on MITRE.

CVE ID

CVE-2026-23991

GHSA ID

GHSA-846p-jg2w-w324

Source code

Credits

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