go-tuf affected by client DoS via malformed server response

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

5.9 · CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

• CVE-2026-23991: 0.58% estimated exploitation activity in the next 30 days; percentile 47.81 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

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.

Published by the source

21 Jan 2026, 16:19 UTC

Last modified by the source

22 Jan 2026, 15:43 UTC

Source last checked

26 Oct 2026, 15:14 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-846p-jg2w-w324

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# Patch Next advisory brief: CVE-2026-23991

Advisory: go-tuf affected by client DoS via malformed server response
IDs: CVE-2026-23991, GHSA-846p-jg2w-w324
Record: https://patchnext.com/advisories/cve-2026-23991 (revision 1, source checked 26 Oct 2026, 15:14 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.9)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/theupdateframework/go-tuf/v2 2.3.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/theupdateframework/go-tuf/v2: affected < 2.3.1; fixed in 2.3.1

## Suggested inspection (read-only)
- Go github.com/theupdateframework/go-tuf/v2: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/theupdateframework/go-tuf/v2.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-846p-jg2w-w324 (GitHub-reviewed advisory GHSA-846p-jg2w-w324 lists affected ranges: Go github.com/theupdateframework/go-tuf/v2 >=0 <2.3.1)

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