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Fencer Vulns
medium 5.9

CVE-2026-49834 json

sigstore-go: Multi-log threshold bypass via single compromised log

published 2026-07-09 4 mo ago modified 2026-10-24 15 d ago also EUVD-2026-45287 , GHSA-9vcr-p3rj-q5q6 , GO-2026-5952

cvss
5.9
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 7%
public exploits
0
none known

Summary

sigstore-go is a Go library for Sigstore signing and verification. Prior to 1.2.0, a verifier configured with WithTransparencyLog(N>1) or WithSignedCertificateTimestamps(N>1) counts verified witnesses per entry or per validation path rather than per log authority, allowing a single compromised transparency log or CT log to satisfy multi-log threshold requirements and defeat the multi-log policy. This issue is fixed in version 1.2.0.

Patch / fix

  • go github.com/sigstore/sigstore-go 1.2.0
  • sigstore sigstore-go 1.2.0
  • sigstore-go Debian 14 1.2.1-1

debian advisories DEBIAN-CVE-2026-49834

  • spire1.15 hummingbird 1 1.15.2-0.3.hum1
  • spire1.15-agent hummingbird 1 1.15.2-0.3.hum1
  • spire1.15-server hummingbird 1 1.15.2-0.3.hum1
  • spire1.15-oidc-discovery-provider hummingbird 1 1.15.2-0.3.hum1
  • trivy hummingbird 1 0.72.0-0.1.3.hum1
  • spire1.14 hummingbird 1 1.14.7-0.3.hum1
  • spire1.14-agent hummingbird 1 1.14.7-0.3.hum1
  • spire1.14-server hummingbird 1 1.14.7-0.3.hum1

red hat advisories RHSA-2026:44162RHSA-2026:47891RHSA-2026:47889

  • govulncheck-vulndb openSUSE Leap 16.0 0.0.20260723T184607-160000.1.1

opensuse advisories openSUSE-SU-2026:21483-1

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-2026-49834 updated cvss 5.9

github.com/sigstore/sigstore-go: sigstore-go: Security Policy Bypass via Compromised Log

  • Red Hat OpenShift Pipelines openshift-pipelines/pipelines-opc-rhel9, openshift-pipelines/pipelines-cli-tkn-rhel8, openshift-pipelines/pipelines-cli-tkn-rhel9, openshift-pipelines/pipelines-rhel9-operator, openshift-pipelines/pipelines-chains-controller-rhel8, openshift-pipelines/pipelines-chains-controller-rhel9
    affected: no fix available “Fix deferred”
  • Red Hat Advanced Cluster Security 4 advanced-cluster-security/rhacs-main-rhel8, advanced-cluster-security/rhacs-main-rhel9, advanced-cluster-security/rhacs-roxctl-rhel8, advanced-cluster-security/rhacs-roxctl-rhel9, advanced-cluster-security/rhacs-rhel8-operator, advanced-cluster-security/rhacs-rhel9-operator, +3 more
    affected: no fix available, no fix planned “Out of support scope”
  • Red Hat OpenShift Dev Spaces devspaces/udi-rhel9
    affected: no fix available “Fix deferred”
  • Red Hat Trusted Artifact Signer rhtas/ec-rhel9, rhtas/cosign-rhel9, rhtas/gitsign-rhel9, rhtas/ctlog-monitor-rhel9, rhtas/rekor-monitor-rhel9, rhtas/rhtas-console-rhel9, +5 more
    affected: no fix available, no fix planned “Out of support scope”
  • Red Hat Web Terminal web-terminal/web-terminal-tooling-rhel9
    affected: no fix planned “Out of support scope”
  • Red Hat Security Profiles Operator compliance/openshift-security-profiles-rhel8-operator, compliance/openshift-security-profiles-operator-bundle 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
    affected: no fix available “Fix deferred”
  • 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: no fix planned “Out of support scope”
  • Red Hat Hardened Images trivy 0.72.0-0.1.3.hum1, spire1.14 1.14.7-0.3.hum1, spire1.15 1.15.2-0.3.hum1
    fixed: vendor fix RHSA-2026:47889
show 1 more
  • Red Hat Hardened Images cosign 3.1.2-0.2.hum1
    not affected: vulnerable code not present

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
3 mo ago

Exploit prediction

0.18% chance of exploitation in the next 30 days, higher than 7% of all scored CVEs (FIRST EPSS, 2026-11-08).

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:H/A:N
GitHub 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Affected packages

ecosystem package affected fixed in
go github.com/sigstore/sigstore-go
<1.2.0
1.2.0

Affected products

  • sigstore sigstore-go

Classification

Weakness
  • CWE-347 Improper Verification of Cryptographic Signature
  • CWE-345 Insufficient Verification of Data Authenticity

References

Sources

Fencer Vulns 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.