# CVE-2026-75939: Openshift/oc-mirror: release signature verification: openpgp signatureerror checked before signed body is consumed

Status: published. Published: 2026-09-21. Updated: 2026-11-06.

A flaw was found in openshift/oc-mirror. The tool incorrectly verifies PGP (Pretty Good Privacy) release image signatures by checking for signature errors before the entire signed body is processed, leading to a bypass of the signature verification. A remote attacker, by intercepting or manipulating network traffic to the signature endpoint, could exploit this to craft a PGP message with a valid Red Hat release key ID but a forged signature. This enables the `oc-mirror` tool to accept and mirror a malicious release payload into a disconnected registry, potentially compromising the integrity of software deployments.

## Remediation

- workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability. (source: CNA: redhat)

## Affected products and versions

- Red Hat / Red Hat OpenShift Container Platform 4.18 (openshift4/oc-mirror-plugin-rhel9): ≥ 1790828598; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat OpenShift Container Platform 4 (openshift4/oc-mirror-plugin-rhel8): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat OpenShift Container Platform 5 (openshift4/oc-mirror-plugin-rhel9): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat OpenShift Container Platform 5 (openshift5/oc-mirror-plugin-rhel9): Version range not reported. Source: CNA: redhat

## Severity and prioritization

- CVSS 3.1: 7.4 (high); CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N; source: CNA: redhat

- CVSS 3.1: 7.4 (high); CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N; source: NVD: secalert@redhat.com

- CISA KEV: No listing in collected sources

- EPSS: 0.38% as of 2026-11-06; percentile 31.90%

- SSVC: exploitation none; automatable no; technical impact total; source ADP: CISA-ADP

- Weaknesses: CWE-347

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://access.redhat.com/errata/RHSA-2026:79039 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/security/cve/CVE-2026-75939 (CNA: redhat; vdb-entry, x_refsource_REDHAT)

- https://bugzilla.redhat.com/show_bug.cgi?id=2517976 (CNA: redhat; issue-tracking, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2026:79039 (secalert@redhat.com)

- https://access.redhat.com/security/cve/CVE-2026-75939 (secalert@redhat.com)

- https://bugzilla.redhat.com/show_bug.cgi?id=2517976 (secalert@redhat.com)

## Provenance

- CNA: redhat: https://www.cve.org/CVERecord?id=CVE-2026-75939; retrieved 2026-11-06; source updated 2026-11-06

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-75939; retrieved 2026-11-07; source updated 2026-11-06

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-75939; retrieved 2026-11-06; source updated Not reported

Revision: 249e6ac441e56e141f825e5468deef502a85d22fe7b10c9a02afb50b90c73ecb

Canonical: https://y2.dev/cve/CVE-2026-75939

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