Skip to content
Fencer Vulns
medium 5.5

CVE-2026-22703 json

Cosign verification accepts any valid Rekor entry under certain conditions

published 2026-01-10 9 mo ago modified 2026-09-10 1 mo ago also BIT-cosign-2026-22703 , EUVD-2026-1868 , GHSA-whqx-f9j3-ch6m , GO-2026-4309

cvss
5.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 1%
public exploits
0
none known

Summary

Cosign provides code signing and transparency for containers and binaries. Prior to versions 2.6.2 and 3.0.4, Cosign bundle can be crafted to successfully verify an artifact even if the embedded Rekor entry does not reference the artifact's digest, signature or public key. When verifying a Rekor entry, Cosign verifies the Rekor entry signature, and also compares the artifact's digest, the user's public key from either a Fulcio certificate or provided by the user, and the artifact signature to the Rekor entry contents. Without these comparisons, Cosign would accept any response from Rekor as valid. A malicious actor that has compromised a user's identity or signing key could construct a valid Cosign bundle by including any arbitrary Rekor entry, thus preventing the user from being able to audit the signing event. This issue has been patched in versions 2.6.2 and 3.0.4.

Patch / fix

  • go github.com/sigstore/cosign/v3 3.0.4
  • go github.com/sigstore/cosign/v2 2.6.2
  • bitnami cosign 2.6.2, 3.0.4
  • sigstore cosign 2.6.2, 3.0.4
  • cosign Debian 14 2.6.2-1

debian advisories DEBIAN-CVE-2026-22703

  • 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 0.0.20260114T191543-150000.1.137.1

suse advisories SUSE-SU-2026:20904-1SUSE-SU-2026:0777-1SUSE-SU-2026:0142-1

  • 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 3.0.4-2.1

opensuse advisories openSUSE-SU-2026:21483-1openSUSE-SU-2026:20386-1openSUSE-SU-2026:10232-1

  • cosign Alpine 3.23 2.6.3-r0

alpine advisories ALPINE-CVE-2026-22703

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

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-2026-22703 updated cvss 5.5

github.com/sigstore/cosign: Cosign verification accepts any valid Rekor entry under certain conditions

  • Red Hat OpenShift Pipelines openshift-pipelines-client, openshift-pipelines/pipelines-opc-rhel9, openshift-pipelines/pipelines-cli-tkn-rhel8, openshift-pipelines/pipelines-cli-tkn-rhel9, openshift-pipelines/pipelines-rhel8-operator, openshift-pipelines/pipelines-rhel9-operator, +7 more Red Hat OpenShift Serverless openshift-serverless-1/kn-plugin-event-sender-rhel9 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/policy-controller-rhel9 Red Hat Web Terminal web-terminal/web-terminal-tooling-rhel9
    +3 more products
    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 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
9 mo ago

Exploit prediction

0.11% chance of exploitation in the next 30 days, higher than 1% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/sigstore/cosign/security/advisories/GHSA-whqx-f9j3-ch6m referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
GitHub 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
OSV 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N

Affected packages

ecosystem package affected fixed in
go github.com/sigstore/cosign/v3
<3.0.4
3.0.4
go github.com/sigstore/cosign/v2
<2.6.2
2.6.2
bitnami cosign
>=2.0.0, <2.6.2
>=3.0.0, <3.0.4
2.6.2
3.0.4
go github.com/sigstore/cosign
all versions
 no fix listed

Affected products

  • sigstore cosign

Classification

Weakness
  • 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.