Is there a patch available for CVE-2026-15791?

Yes, a patch is available for CVE-2026-15791. Update the affected software to the latest version immediately.

BuildKit CVE-2026-15791

Q: What is the CVSS score of CVE-2026-15791?

CVE-2026-15791 has a CVSS 4.0 base score of 1.8 (Low). CVSS vector: CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:A/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. EPSS exploitation probability: 0.2%.

EUVD-2026-46310 LOW

Path Traversal (CWE-22)

2026-07-21 Docker

Path Traversal Moby Buildkit

1.8

CVSS 4.0 · Vendor: Docker

Severity by source

Vendor (Docker) PRIMARY

1.8 LOW

CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:A/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

vuln.today AI

5.0 MEDIUM

Local vector with scope change to host /tmp; no privileges required but user interaction (active build session) needed; no confidentiality impact, low integrity and availability.

3.1 AV:L/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:L

4.0 AV:L/AC:L/AT:P/PR:N/UI:A/VC:N/VI:L/VA:L/SC:N/SI:L/SA:N

Primary rating from Vendor (Docker).

CVSS VectorVendor: Docker

Attack Vector

Local

Attack Complexity

Low

Privileges Required

None

User Interaction

Scope

Lifecycle Timeline

Patch available

Jul 21, 2026 - 19:03 EUVD

CVSS changed

Jul 21, 2026 - 17:22 NVD

3.3 (LOW) 1.8 (LOW)

Analysis Generated

Jul 21, 2026 - 16:47 vuln.today

CVE Published

Jul 21, 2026 - 16:10 cve.org

LOW 3.3

DescriptionCVE.org

A crafted message in the BuildKit low-level build API can be used to remove the contents of the /tmp directory. The action that can normally be used to delete files inside the build container rootfs can escape into the real host temp directory.

AnalysisAI

Path traversal in BuildKit's low-level build API allows crafted messages to redirect the container rootfs file-deletion action onto the real host /tmp directory, wiping its contents. All published moby/buildkit versions are affected per the broad CPE cpe:2.3:a:moby:buildkit:*:*:*:*:*:*:*:*. No public exploit code or active exploitation has been identified at time of analysis; the vendor-assigned CVSS score of 3.3 (CVSS 4.0) correctly reflects a constrained impact - host /tmp destruction rather than arbitrary code execution or credential exposure.

Technical ContextAI

BuildKit is Moby's low-level container image build engine, used as the backend for 'docker build' and similar tooling. It exposes a gRPC-based API that clients use to send build instructions, including file system operations against the build container's rootfs. The root cause is CWE-22 (Improper Limitation of a Pathname to a Restricted Directory - 'Path Traversal'): the file-deletion operation fails to canonicalize or jail the target path, allowing a crafted path in the API message to traverse out of the container rootfs mount and resolve to the host filesystem's /tmp directory. The affected CPE cpe:2.3:a:moby:buildkit:*:*:*:*:*:*:*:* covers all version branches, indicating the flaw is not version-range-limited. The CVSS 4.0 vector (AV:L/AT:P) confirms exploitation requires local access and a specific attack precondition - typically the ability to submit messages to the BuildKit daemon's low-level API, not just the high-level 'docker build' CLI.

RemediationAI

Upgrade to the patched BuildKit release identified in the GitHub Security Advisory at https://github.com/moby/buildkit/security/advisories/GHSA-32pv-7hq5-qhwq - the exact fix version is not confirmed from available data and must be taken directly from the advisory. As a compensating control pending upgrade, restrict access to the BuildKit low-level gRPC API socket (typically /run/buildkit/buildkitd.sock) to only trusted, authorized build clients; this trades off build flexibility for a reduced attack surface. Additionally, consider running the BuildKit daemon in rootless mode, which limits the blast radius of a host /tmp traversal since the effective 'host /tmp' visible to the daemon is scoped to the user's namespace. Do not expose the BuildKit API over a network listener (AV:L confirms the expected local vector) as a defense-in-depth measure.