CVE-2026-23991: Github.com/theupdateframework/go tuf/v2 Denial of Service Vulnerability

MODERATE
Advisory Identifier: GHSA-846p-jg2w-w324
Share
CVSS 5.9
CWE-617 CWE-754
Published
Advisory Summary

CVE-2026-23991 is a MODERATE (CVSS 5.9) denial of service vulnerability (CWE-617: Reachable Assertion) affecting Github.com/theupdateframework/go tuf/v2 libraries in the Go ecosystem. The issue involves go-tuf affected by client dos via malformed server response. Remediation is available by upgrading affected packages to version 2.3.1.

CVE-2026-23991 at a Glance

CVE Identifier CVE-2026-23991
GHSA Identifier GHSA-846p-jg2w-w324
Severity MODERATE
CVSS v3.1 Base Score 5.9
CWE Classification CWE-617: Reachable Assertion
Affected Product Github.com/theupdateframework/go tuf/v2
Package Ecosystem Go
Published Date
Last Updated

Security Impact

CVSS: 5.9

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H).

Attack Vector Network (AV:N)
Attack Complexity High (AC:H)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity None (I:N)
Availability High (A:H)

How to Fix CVE-2026-23991

To remediate this vulnerability, upgrade all affected Github.com/theupdateframework/go tuf/v2 dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

github.com/theupdateframework/go-tuf/v2 fixed: 2.3.1 
Upgrade github.com/theupdateframework/go-tuf/v2 to 2.3.1
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for github.com/theupdateframework/go-tuf/v2

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-23991, inspect your project dependencies for Github.com/theupdateframework/go tuf/v2:

inspect dependencies for github.com/theupdateframework/go-tuf/v2

Analyze the terminal output to locate any version of Github.com/theupdateframework/go tuf/v2 in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2.3.1), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-617: Reachable Assertion, where 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. In Github.com/theupdateframework/go tuf/v2, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

# 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.

CVE-2026-23991 Affected Github.com/theupdateframework/go tuf/v2 Versions

1 component(s)
Fixed Versions:
2.3.1
Product / Package Ecosystem Affected Versions Fixed Version
github.com/theupdateframework/go-tuf/v2
golang/github.com/theupdateframework/go-tuf/v2
Go
< 2.3.1
2.3.1

References

GitHub Advisory / Wiki ADVISORY
https://github.com/theupdateframework/go-tuf/security/advisories/GHSA-846p-jg2w-w324
NVD — CVE-2026-23991 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-23991
Security Fix Commit FIX COMMIT
https://github.com/theupdateframework/go-tuf/commit/73345ab6b0eb7e59d525dac17a428f043074cef6
Github.com/theupdateframework/go tuf/v2 Source Repository REPOSITORY
https://github.com/theupdateframework/go-tuf
Github.com/theupdateframework/go tuf/v2 Release RELEASE
https://github.com/theupdateframework/go-tuf/releases/tag/v2.3.1

Frequently Asked Questions

What is CVE-2026-23991?
CVE-2026-23991 is a security vulnerability in Github.com/theupdateframework/go tuf/v2 involving go-tuf affected by client DoS via malformed server response under CWE-617: Reachable Assertion.
Which Github.com/theupdateframework/go tuf/v2 versions are affected?
Affected versions include releases prior to 2.3.1 across affected packages: github.com/theupdateframework/go-tuf/v2.
What version fixes CVE-2026-23991?
Upgrading to 2.3.1 (or the latest patched release for your respective branch) resolves the vulnerability.
Is github.com/theupdateframework/go-tuf/v2 affected?
Yes, github.com/theupdateframework/go-tuf/v2 is affected in releases prior to 2.3.1. Upgrade your dependency to 2.3.1 or later.
What is the CVSS score of CVE-2026-23991?
CVE-2026-23991 has a CVSS v3.1 base score of 5.9 (MODERATE) with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H.
What CWE is associated with CVE-2026-23991?
CVE-2026-23991 is classified under CWE-617: 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.).
How can I check Go dependencies for CVE-2026-23991?
Run the dependency tree command: 'inspect dependencies for github.com/theupdateframework/go-tuf/v2'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-846p-jg2w-w324",
  "modified" : "2026-01-22T15:43:38Z",
  "published" : "2026-01-21T16:19:28Z",
  "aliases" : [ "CVE-2026-23991" ],
  "summary" : "go-tuf affected by client DoS via malformed server response",
  "details" : "# Security Disclosure: Client DoS via malformed server response\n\n## Summary\n\nIf 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.\n\n## Impact \n\nClient crashes upon receiving and parsing malformed TUF metadata. This can cause long running services to enter an restart/crash loop.\n\n## Workarounds\n\nNone currently. \n\n## Affected code\n\nThe `metadata.checkType` function did not properly type assert the (untrusted) input causing it to panic on malformed data.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/theupdateframework/go-tuf/v2"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "2.3.1"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/theupdateframework/go-tuf/security/advisories/GHSA-846p-jg2w-w324"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-23991"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/theupdateframework/go-tuf/commit/73345ab6b0eb7e59d525dac17a428f043074cef6"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/theupdateframework/go-tuf"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/theupdateframework/go-tuf/releases/tag/v2.3.1"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-617", "CWE-754" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-01-21T16:19:28Z",
    "nvd_published_at" : "2026-01-22T03:15:47Z"
  }
}