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Fencer Intel
medium 5.9

CVE-2026-23991 json

go-tuf affected by client DoS via malformed server response

published 9mo ago modified last mo. also EUVD-2026-3673 , GHSA-846p-jg2w-w324 , GO-2026-4348

cvss
5.9
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 48%
public exploits
0
none known

Summary

go-tuf is a Go implementation of The Update Framework (TUF). Starting in version 2.0.0 and prior to version 2.3.1, 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 denial of service. 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. Version 2.3.1 fixes the issue. No known workarounds are available.

Patch / fix

  • go github.com/theupdateframework/go-tuf/v2 2.3.1
  • theupdateframework go-tuf 2.3.1
  • golang-github-theupdateframework-go-tuf Debian 14 2.4.1+0.7.0-1

debian advisories DEBIAN-CVE-2026-23991

  • cosign SLES for SAP applications 16.0, SLES 16.0 3.0.5-160000.1.1
  • cosign SLE Module for Basesystem 15 SP7, openSUSE Leap 15.6 3.0.5-150400.3.35.1
  • govulncheck-vulndb openSUSE Leap 15.6 0.0.20260226T182644-150000.1.149.1
  • govulncheck-vulndb openSUSE Leap 15.6 0.0.20260205T172317-150000.1.146.1

suse advisories SUSE-SU-2026:20904-1SUSE-SU-2026:0777-1SUSE-SU-2026:0757-1SUSE-SU-2026:0403-1

  • govulncheck-vulndb openSUSE Leap 16.0 0.0.20260723T184607-160000.1.1
  • cosign openSUSE Leap 16.0 3.0.5-160000.1.1
  • cosign openSUSE Tumbleweed 3.0.5-1.1

opensuse advisories openSUSE-SU-2026:21483-1openSUSE-SU-2026:20386-1openSUSE-SU-2026:10235-1

  • gh Azure Linux 3.0 2.62.0-13

azure linux advisories AZL-75186

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Is CVE-2026-23991 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-23991 updated cvss 5.9

github.com/theupdateframework/go-tuf/v2: go-tuf client DoS via malformed server response

  • Red Hat OpenShift Pipelines openshift-pipelines/pipelines-opc-rhel9, openshift-pipelines/pipelines-cli-tkn-rhel9, openshift-pipelines/pipelines-rhel8-operator, openshift-pipelines/pipelines-rhel9-operator, openshift-pipelines/pipelines-operator-bundle, openshift-pipelines/pipelines-operator-proxy-rhel8, +4 more Red Hat Advanced Cluster Security 4 advanced-cluster-security/rhacs-main-rhel8, advanced-cluster-security/rhacs-roxctl-rhel8, advanced-cluster-security/rhacs-rhel8-operator, advanced-cluster-security/rhacs-central-db-rhel8, advanced-cluster-security/rhacs-scanner-v4-rhel8, advanced-cluster-security/rhacs-scanner-v4-db-rhel8 Red Hat OpenShift Dev Spaces devspaces/udi-rhel9 Red Hat Trusted Artifact Signer rhtas/cosign-rhel9, rhtas/gitsign-rhel9, rhtas/client-server-rhel9, rhtas/rhtas-console-rhel9, rhtas/policy-controller-rhel9, rhtas/policy-controller-rhel9-operator, +1 more Red Hat Web Terminal web-terminal/web-terminal-tooling-rhel9 Red Hat Security Profiles Operator compliance/openshift-security-profiles-rhel8-operator, compliance/openshift-security-profiles-operator-bundle
    +2 more products
    Red Hat Zero Trust Workload Identity Manager zero-trust-workload-identity-manager/spiffe-spire-agent-rhel9, zero-trust-workload-identity-manager/spiffe-spire-server-rhel9, zero-trust-workload-identity-manager/spiffe-spire-oidc-discovery-provider-rhel9 Red Hat Zero Trust Workload Identity Manager - Tech Preview zero-trust-workload-identity-manager/spiffe-spire-agent-rhel9, zero-trust-workload-identity-manager/spiffe-spire-server-rhel9, zero-trust-workload-identity-manager/spiffe-spire-oidc-discovery-provider-rhel9, zero-trust-workload-identity-manager/zero-trust-workload-identity-manager-rhel9, zero-trust-workload-identity-manager/zero-trust-workload-identity-manager-operator-bundle
    affected: workaround, no fix available “Fix deferred”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
9mo ago

Exploit prediction

0.58% chance of exploitation in the next 30 days, higher than 48% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
GitHub 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
go github.com/theupdateframework/go-tuf/v2
<2.3.1
2.3.1

Affected products

  • theupdateframework go-tuf

Classification

Weakness
  • CWE-617 Reachable Assertion
  • CWE-754 Improper Check for Unusual or Exceptional Conditions

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.