CVE-2026-121520
Privilege escalation via unauthorized extended file attribute modification
CVE-2026-121520: Privilege escalation via unauthorized extended file attribute modification. Not in the CISA KEV catalog.
Compare the source-linked records below. Ratings and product/version details belong to each advisory; they are not a single CVE-wide score or proof that every listed product is affected. How VulniPulse collects and checks evidence.
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CVE-2026-121520 key facts
- CISA KEV
- Not listed (catalog checked )
- Highest advisory severity
- High
- CVSS base score
- 7.9 (Red Hat), 4.5 (Docker)
- Weakness
- CWE-22
- Fixed releases
- Docker: 0.34.1
- VulniPulse record
- Published · Updated
Scores, vectors, weaknesses and fixed releases are quoted from vendor advisories that cover only CVE-2026-121520; bulletin-wide values are not repeated here.
Is CVE-2026-121520 exploited?
No exploitation is reported in the sources VulniPulse tracks: CVE-2026-121520 is not in the CISA KEV catalog (checked ) and no tracked advisory for it reports exploitation. That is not proof the vulnerability cannot be exploited.
How do I fix CVE-2026-121520?
Upgrade to a fixed release named by the vendor:
- Docker: 0.34.1
- Restrict access to the BuildKit control API socket and network endpoints to trusted administrative operators using strict file system permissions and mutual TLS. In multi-tenant environments, isolate build execution within dedicated, ephemeral virtual machines rather than sharing the daemon across untrusted tenants. (Red Hat)
Vendor advisory comparison
Docker
1 advisory- Advisory severityMedium4.5
Medium [CVE-2026-121520] In BuildKit versions prior to v0.34.1, a malicious client with access to the BuildKit control APIs can submit a build request that sets an extended attribute on a file outside the BuildKit state directory
CVE-2026-121520Source published Source updated
In BuildKit versions prior to v0.34.1, a malicious client with access to the BuildKit control APIs can submit a build request that sets an extended attribute on a file outside the BuildKit state directory. Extended attributes in the trusted. or security. namespaces may also be set, potentially giving a program on the host elevated privileges. This issue affects build services that accept build requests from untrusted users. The issue is fixed in v0.34.1.
- Affected products in this advisory
- BuildKit
- Source-reported affected versions
- before 0.34.1
- Source-reported fixed versions
- 0.34.1
- Mitigation guidance
- No mitigation guidance extracted; consult the source.
Red Hat
1 advisory- Advisory severityHigh7.9
High [CVE-2026-121520] Privilege escalation via unauthorized extended file attribute modification
CVE-2026-121520Source published Source updated
Privilege escalation via unauthorized extended file attribute modification. Red Hat rates this important (CVSS 7.9). Weakness: CWE-22. Affected products named by the advisory: Assisted Installer for Red Hat OpenShift Container Platform 2; Compliance Operator; Confidential Compute Attestation; Custom Metric Autoscaler operator for Red Hat Openshift; and 37 more.
- Related products — impact not confirmed
- Assisted Installer for Red Hat OpenShift Container Platform 2
- Compliance Operator
- Confidential Compute Attestation
- Custom Metric Autoscaler operator for Red Hat Openshift
37 more entries in the full advisory.
- Source-reported affected versions
- Affected-version details not available in this record.
- Source-reported fixed versions
- No fixed-version detail extracted. This does not mean no fix exists.
- Mitigation guidance
- Restrict access to the BuildKit control API socket and network endpoints to trusted administrative operators using strict file system permissions and mutual TLS. In multi-tenant environments, isolate build execution within dedicated, ephemeral virtual machines rather than sharing the daemon across untrusted tenants.
More Docker advisories
- CVE-2026-121522Nov 3, 2026In BuildKit versions v0.26.0 through v0.34.1, a specific build definition that resolves
- CVE-2026-93321Oct 5, 2026Docker: malicious frontend can submit an LLB definition that causes buildkitd to panic
- CVE-2026-93315Oct 5, 2026Docker: When proxy networking with CA injection is enabled, a build can modify its CA
- CVE-2026-93326Oct 5, 2026Docker: build step for a Git source, crafted in a specific way, can bypass some policy
- CVE-2026-93323Oct 5, 2026The Dockerfile frontend loaded the Dockerfile and.dockerignore files of a build context
- CVE-2026-93322Oct 5, 2026Docker: malicious frontend can submit an LLB definition that causes buildkitd to panic
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