BuildKit proxy CA cleanup can be disrupted by build steps

{
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "cveMetadata": {
    "cveId": "CVE-2026-93315",
    "assignerOrgId": "686469e6-3ff6-451b-ab8b-cf5b9e89401e",
    "assignerShortName": "Docker",
    "dateUpdated": "2026-10-05T21:57:08.053Z",
    "dateReserved": "2026-09-17T17:17:25.321Z",
    "datePublished": "2026-10-05T21:57:08.053Z",
    "state": "PUBLISHED"
  },
  "containers": {
    "cna": {
      "providerMetadata": {
        "orgId": "686469e6-3ff6-451b-ab8b-cf5b9e89401e",
        "shortName": "Docker",
        "dateUpdated": "2026-10-05T21:57:08.053Z"
      },
      "title": "BuildKit proxy CA cleanup can be disrupted by build steps",
      "descriptions": [
        {
          "lang": "en",
          "value": "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.",
          "supportingMedia": [
            {
              "type": "text/html",
              "base64": false,
              "value": "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."
            }
          ]
        }
      ],
      "affected": [
        {
          "vendor": "moby",
          "product": "BuildKit",
          "packageName": "github.com/moby/buildkit",
          "platforms": [
            "Linux"
          ],
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "0.31.0",
              "status": "affected",
              "versionType": "semver",
              "lessThan": "0.33.1"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "lang": "en",
              "description": "CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition",
              "cweId": "CWE-367",
              "type": "CWE"
            }
          ]
        }
      ],
      "references": [
        {
          "url": "https://github.com/moby/buildkit/security/advisories/GHSA-2f5p-x9ph-g97x",
          "tags": [
            "vendor-advisory"
          ]
        },
        {
          "url": "https://github.com/moby/buildkit/releases/tag/v0.33.1",
          "tags": [
            "patch"
          ]
        }
      ],
      "metrics": [
        {
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "workarounds": [
        {
          "lang": "en",
          "value": "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.",
          "supportingMedia": [
            {
              "type": "text/html",
              "base64": false,
              "value": "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."
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "value": "Zhenchen Wang (Institute of Software, Chinese Academy of Sciences), Shuo Huai, Songlin Zhu, Weijie Liu, and Yan Jia (Nankai University)",
          "type": "finder"
        }
      ]
    }
  }
}