CVE-2026-100838 (GCVE-0-2026-100838)

Vulnerability from cvelistv5 – Published: 2026-09-27 01:28 – Updated: 2026-09-27 01:28
VLAI
Title
Contrast before 1.19.1 CopyFile Policy Symlink Subversion
Summary
Contrast is a confidential-computing runtime for Kubernetes. In versions before 1.19.1, the Kata agent policies generated by the Contrast CLI contained a flaw in the CopyFile verification that allowed arbitrary writes to the guest root filesystem. A malicious process on the untrusted host able to connect to the Kata agent VSOCK could issue a series of CopyFile requests to overwrite security-critical files in the guest or trick the workload into disclosing sensitive data, effectively amounting to a full guest takeover. Users unable to upgrade can apply an equivalent rego policy fix passed to 'contrast generate --policy'.
Severity
8.6 (High)
CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
8.1 (High)
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
CWE
  • CWE-59 - Improper Link Resolution Before File Access ('Link Following')
Assigner
References
Impacted products
Vendor Product Version CPE status
edgelesssys contrast Affected: 0 , < 1.19.1 (semver)
Unaffected: 1.19.1 (semver)
guessed Create a notification for this product.
Date Public
2026-04-23 00:00
Show details on NVD website
To clipboard 

{
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      "descriptions": [
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        }
      ],
      "metrics": [
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            "attackRequirements": "NONE",
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            "privilegesRequired": "NONE",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "vectorString": "CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N",
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            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
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      ],
      "problemTypes": [
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          "descriptions": [
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              "description": "Improper Link Resolution Before File Access (\u0027Link Following\u0027)",
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              "type": "CWE"
            }
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      "providerMetadata": {
        "dateUpdated": "2026-09-27T01:28:35.498Z",
        "orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
        "shortName": "VulnCheck"
      },
      "references": [
        {
          "name": "GitHub Security Advisory (GHSA-rh99-wc69-c255)",
          "tags": [
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          ],
          "url": "https://github.com/edgelesssys/contrast/security/advisories/GHSA-rh99-wc69-c255"
        },
        {
          "name": "VulnCheck Advisory: Contrast before 1.19.1 CopyFile Policy Symlink Subversion",
          "tags": [
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          ],
          "url": "https://www.vulncheck.com/advisories/contrast-before-1.19.1-copyfile-policy-symlink-subversion"
        }
      ],
      "title": "Contrast before 1.19.1 CopyFile Policy Symlink Subversion",
      "x_generator": {
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  "cveMetadata": {
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    "assignerShortName": "VulnCheck",
    "cveId": "CVE-2026-100838",
    "datePublished": "2026-09-27T01:28:35.498Z",
    "dateReserved": "2026-09-26T23:23:03.411Z",
    "dateUpdated": "2026-09-27T01:28:35.498Z",
    "state": "PUBLISHED"
  },
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    "nvd": {
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          }
        ],
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        "lastModified": "2026-09-28T15:23:38.510",
        "metrics": {
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          "cvssMetricV40": [
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                "Recovery": "NOT_DEFINED",
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                "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",
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                "valueDensity": "NOT_DEFINED",
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    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.