CVE-2026-93315

BuildKit proxy CA cleanup can be disrupted by build steps

Published Oct 5, 2026 CVSS 4.0 · 5.8 Medium EPSS < 1% KEV · Not listed

Description

When proxy networking with CA injection is enabled, a build can modify its CA bundle before cleanup. This may cause cleanup to block, operate outside the build rootfs, or fail without failing the build.

Analysis

Technical impact

When proxy networking with CA injection is enabled, a build can modify its CA bundle prior to cleanup. This can result in the cleanup process blocking, running outside the build root filesystem, or failing without causing the build to fail. The flaw is classified as CWE‑367, indicating improper cleanup of a resource.

Affected Systems

The moby BuildKit component is affected. No specific version ranges are listed in the advisory; users should consult the latest release notes for guidance.

Risk and Exploitability

The CVSS score of 5.8 classifies the vulnerability as moderate. EPSS score is not available, and it is not listed in the CISA KEV catalog. The likely attack vector is through build steps that enable proxy networking and alter the CA bundle. Exploitation requires the build environment to be configured for proxy networking and to modify the injected CA bundle. No evidence is presented of successful exploitation beyond the potential for residual certificates.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

moby

BuildKit

unaffected

Version	Status	Constraints
`0.31.0`	affected	< 0.33.1

No data.

Vendor Product Versions

Moby

Buildkit

Version	Status	Scheme	Platform
`[0.31.0,0.33.1)`	affected	semver	['linux']

Remediation

Vendor Workaround

Avoid using build sources from untrusted locations. Only builds enabling proxy networking for exec steps (either via BuildKitd TOML config or Buildx Rego policy) are affected.

OpenCVE Recommended Actions

Apply the official workaround: avoid using build sources from untrusted locations and restrict builds that enable proxy networking for exec steps; only builds that use proxy networking are affected.
Upgrade to the latest stable BuildKit release (for example, v0.33.1 or later), which may resolve the cleanup issue.
If upgrading is not possible, monitor build logs for unexpected CA changes and consider implementing a manual cleanup step after each build to ensure certificates are removed.

Generated by OpenCVE AI on October 6, 2026 at 00:05 UTC.

Tracking

Advisories

No advisories available

Metrics

Attack Vector Local

Attack Complexity Low

Privileges Required Low

Attack Requirements Present

User Interaction None

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact Low

Vulnerable System Availability Impact High

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact Low

Subsequent System Availability Impact None

No CVSS v3.1

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.096% probability within 30 days)

Exploitation none

Automatable no

Technical Impact partial

References

Link	Providers
https://github.com/moby/buildkit/releases/tag/v0.33.1
https://github.com/moby/buildkit/security/advisories/GHSA-2f5p-x9ph-g97x

History

Oct 6, 2026 2:30 PM Scoring metrics updated View changes

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}`

Oct 5, 2026 11:45 PM First appearance in the feed. Affected vendors updated View changes

Type	Values Removed	Values Added
First Time appeared		Moby Moby buildkit
Vendors & Products		Moby Moby buildkit

Oct 5, 2026 10:00 PM Description updated. Title updated. Weaknesses updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
Description		When proxy networking with CA injection is enabled, a build can modify its CA bundle before cleanup. This may cause cleanup to block, operate outside the build rootfs, or fail without failing the build.
Title		BuildKit proxy CA cleanup can be disrupted by build steps
Weaknesses		CWE-367
References		https://github.com/moby/buildkit/releases/tag/v0.33.1 https://github.com/moby/buildkit/security/advisories/GHSA-2f5p-x9ph-g97x
Metrics		cvssV4_0 `{'score': 5.8, 'vector': 'CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:L/VA:H/SC:N/SI:L/SA:N'}`