FKIE_CVE-2026-105768

Vulnerability from fkie_nvd - Published: 2026-10-05 21:16 - Updated: 2026-10-05 21:16
Severity
6.3 (Medium) - CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N
Summary
apko allows users to build and publish OCI container images built from apk packages. From version 0.2.0 to before version 1.4.5, UserEntry.Parse and GroupEntry.Parse in pkg/passwd read the UID and GID fields of /etc/passwd and /etc/group entries with strconv.Atoi and convert them to uint32 without a range check. On 64-bit platforms an out-of-range value such as 4294967296 (2^32) is truncated to 0, and negative values wrap. Because apko parses the passwd and group entries supplied by the packages it installs and writes them back into the image, an attacker who controls a package installed into the image can ship an entry that appears to declare an unprivileged UID or GID but is written into the built image as UID 0 or GID 0 (root). The truncated UID is also used when resolving the image's run-as user. This issue has been fixed in version 1.4.5.
References
82cea9a6-e9e3-46fe-bdb0-3673de380178https://github.com/chainguard-dev/apko/commit/739e7ce3f675ffb232e16849b51ff93657f1570c
82cea9a6-e9e3-46fe-bdb0-3673de380178https://github.com/chainguard-dev/apko/pull/2516
82cea9a6-e9e3-46fe-bdb0-3673de380178https://github.com/chainguard-dev/apko/releases/tag/v1.4.5
82cea9a6-e9e3-46fe-bdb0-3673de380178https://github.com/chainguard-dev/apko/security/advisories/GHSA-rj6x-hwpv-vhvf
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "collectionURL": "https://pkg.go.dev",
          "defaultStatus": "unaffected",
          "modules": [
            "pkg/passwd"
          ],
          "packageName": "chainguard.dev/apko",
          "product": "apko",
          "programFiles": [
            "pkg/passwd/passwd.go",
            "pkg/passwd/group.go"
          ],
          "programRoutines": [
            {
              "name": "passwd.UserEntry.Parse"
            },
            {
              "name": "passwd.GroupEntry.Parse"
            }
          ],
          "repo": "https://github.com/chainguard-dev/apko",
          "vendor": "chainguard-dev",
          "versions": [
            {
              "lessThan": "1.4.5",
              "status": "affected",
              "version": "0.2.0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "source": "82cea9a6-e9e3-46fe-bdb0-3673de380178"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "apko allows users to build and publish OCI container images built from apk packages. From version 0.2.0 to before version 1.4.5, UserEntry.Parse and GroupEntry.Parse in pkg/passwd read the UID and GID fields of /etc/passwd and /etc/group entries with strconv.Atoi and convert them to uint32 without a range check. On 64-bit platforms an out-of-range value such as 4294967296 (2^32) is truncated to 0, and negative values wrap. Because apko parses the passwd and group entries supplied by the packages it installs and writes them back into the image, an attacker who controls a package installed into the image can ship an entry that appears to declare an unprivileged UID or GID but is written into the built image as UID 0 or GID 0 (root). The truncated UID is also used when resolving the image\u0027s run-as user. This issue has been fixed in version 1.4.5."
    }
  ],
  "id": "CVE-2026-105768",
  "lastModified": "2026-10-05T21:16:36.027",
  "metrics": {
    "cvssMetricV40": [
      {
        "cvssData": {
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "attackComplexity": "LOW",
          "attackRequirements": "PRESENT",
          "attackVector": "NETWORK",
          "availabilityRequirement": "NOT_DEFINED",
          "baseScore": 6.3,
          "baseSeverity": "MEDIUM",
          "confidentialityRequirement": "NOT_DEFINED",
          "exploitMaturity": "NOT_DEFINED",
          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "privilegesRequired": "NONE",
          "providerUrgency": "NOT_DEFINED",
          "subAvailabilityImpact": "NONE",
          "subConfidentialityImpact": "NONE",
          "subIntegrityImpact": "LOW",
          "userInteraction": "NONE",
          "valueDensity": "NOT_DEFINED",
          "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/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",
          "version": "4.0",
          "vulnAvailabilityImpact": "NONE",
          "vulnConfidentialityImpact": "NONE",
          "vulnIntegrityImpact": "LOW",
          "vulnerabilityResponseEffort": "NOT_DEFINED"
        },
        "source": "82cea9a6-e9e3-46fe-bdb0-3673de380178",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-10-05T21:16:35.913",
  "references": [
    {
      "source": "82cea9a6-e9e3-46fe-bdb0-3673de380178",
      "url": "https://github.com/chainguard-dev/apko/commit/739e7ce3f675ffb232e16849b51ff93657f1570c"
    },
    {
      "source": "82cea9a6-e9e3-46fe-bdb0-3673de380178",
      "url": "https://github.com/chainguard-dev/apko/pull/2516"
    },
    {
      "source": "82cea9a6-e9e3-46fe-bdb0-3673de380178",
      "url": "https://github.com/chainguard-dev/apko/releases/tag/v1.4.5"
    },
    {
      "source": "82cea9a6-e9e3-46fe-bdb0-3673de380178",
      "url": "https://github.com/chainguard-dev/apko/security/advisories/GHSA-rj6x-hwpv-vhvf"
    }
  ],
  "sourceIdentifier": "82cea9a6-e9e3-46fe-bdb0-3673de380178",
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-197"
        }
      ],
      "source": "82cea9a6-e9e3-46fe-bdb0-3673de380178",
      "type": "Secondary"
    }
  ]
}



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