Vulnerability-Lookup

GHSA-C3WQ-J5VH-68RC

Vulnerability from github – Published: 2026-06-19 17:45 – Updated: 2026-06-19 17:45

Summary

Hugo: Symlink confinement bypass in os.ReadFile

Details

Affected versions: v0.123.0 through v0.163.0. Earlier versions are not affected. Fixed in: v0.163.1. Severity: Medium. Requires the attacker to be able to place (or convince a site author to place) a symlink inside a mounted directory — for example, inside a locally-vendored theme under themes/. Themes mounted as Go modules from GitHub have symlinks stripped on download and are not affected. Multi-directory walks (e.g. content/asset walking) were not affected either; only direct lookups via resources.Get followed symlinks.

Description. Hugo's virtual filesystem is designed so that files under a mount cannot reach outside the mount tree. A regression introduced in v0.123.0 caused RootMappingFs.statRoot to call Stat (which follows symlinks) instead of Lstat, so a direct os.ReadFile "somefile" where somefile was a symlink pointing outside the mount would return the target's contents. This effectively let a symlink planted inside a theme or local mount read arbitrary files reachable to the user running hugo.

Severity

6.0 (Medium)


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

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{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/gohugoio/hugo"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.123.0"
            },
            {
              "fixed": "0.163.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [],
  "database_specific": {
    "cwe_ids": [
      "CWE-59"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-06-19T17:45:38Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "**Affected versions:** v0.123.0 through v0.163.0. Earlier versions are not affected.\n**Fixed in:** v0.163.1.\n**Severity:** Medium. Requires the attacker to be able to place (or convince a site author to place) a symlink inside a mounted directory \u2014 for example, inside a locally-vendored theme under `themes/`. Themes mounted as Go modules from GitHub have symlinks stripped on download and are not affected. Multi-directory walks (e.g. content/asset walking) were not affected either; only direct lookups via `resources.Get` followed symlinks.\n\n**Description.** Hugo\u0027s virtual filesystem is designed so that files under a mount cannot reach outside the mount tree. A regression introduced in v0.123.0 caused `RootMappingFs.statRoot` to call `Stat` (which follows symlinks) instead of `Lstat`, so a direct `os.ReadFile \"somefile\"` where `somefile` was a symlink pointing outside the mount would return the target\u0027s contents. This effectively let a symlink planted inside a theme or local mount read arbitrary files reachable to the user running `hugo`.",
  "id": "GHSA-c3wq-j5vh-68rc",
  "modified": "2026-06-19T17:45:38Z",
  "published": "2026-06-19T17:45:38Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/gohugoio/hugo/security/advisories/GHSA-c3wq-j5vh-68rc"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/gohugoio/hugo"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:H/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Hugo: Symlink confinement bypass in os.ReadFile"
}

CVE-2026-58403 (GCVE-0-2026-58403)

Vulnerability from cvelistv5 – Published: 2026-07-06 19:25 – Updated: 2026-07-06 20:51

Title

Hugo symlink confinement bypass in os.ReadFile

Summary

Hugo is a static site generator. From v0.123.0 through v0.163.0, Hugo's virtual filesystem is designed so that files under a mount cannot reach outside the mount tree, but a regression caused RootMappingFs.statRoot to call Stat, which follows symlinks, instead of Lstat, so a direct os.ReadFile "somefile" where somefile was a symlink pointing outside the mount would return the target's contents. This effectively let a symlink planted inside a theme or local mount read arbitrary files reachable to the user running hugo. This issue is fixed in v0.163.1.

Severity

5.9 (Medium)


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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-07-06 20:51 UTC

CWE

CWE-59 - Improper Link Resolution Before File Access ('Link Following')

Assigner

GitHub_M mitre root

References

4 references

URL	Tags
https://github.com/gohugoio/hugo/security/advisor…	x_refsource_CONFIRM
https://github.com/gohugoio/hugo/pull/15020	x_refsource_MISC
https://github.com/gohugoio/hugo/commit/cf9c8f93c…	x_refsource_MISC
https://github.com/gohugoio/hugo/releases/tag/v0.163.1	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
gohugoio	hugo	Affected: >= 0.123.0, < 0.163.1

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JSON

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-58403",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-07-06T20:51:16.911843Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-07-06T20:51:27.624Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "hugo",
          "vendor": "gohugoio",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 0.123.0, \u003c 0.163.1"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Hugo is a static site generator. From v0.123.0 through v0.163.0, Hugo\u0027s virtual filesystem is designed so that files under a mount cannot reach outside the mount tree, but a regression caused RootMappingFs.statRoot to call Stat, which follows symlinks, instead of Lstat, so a direct os.ReadFile \"somefile\" where somefile was a symlink pointing outside the mount would return the target\u0027s contents. This effectively let a symlink planted inside a theme or local mount read arbitrary files reachable to the user running hugo. This issue is fixed in v0.163.1."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "LOW",
            "attackRequirements": "PRESENT",
            "attackVector": "NETWORK",
            "baseScore": 5.9,
            "baseSeverity": "MEDIUM",
            "privilegesRequired": "NONE",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "ACTIVE",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "NONE",
            "vulnConfidentialityImpact": "HIGH",
            "vulnIntegrityImpact": "NONE"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-59",
              "description": "CWE-59: Improper Link Resolution Before File Access (\u0027Link Following\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-06T19:25:45.971Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/gohugoio/hugo/security/advisories/GHSA-c3wq-j5vh-68rc",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/gohugoio/hugo/security/advisories/GHSA-c3wq-j5vh-68rc"
        },
        {
          "name": "https://github.com/gohugoio/hugo/pull/15020",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/gohugoio/hugo/pull/15020"
        },
        {
          "name": "https://github.com/gohugoio/hugo/commit/cf9c8f93ca2a2838ce378f9e36d052ac2f79e229",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/gohugoio/hugo/commit/cf9c8f93ca2a2838ce378f9e36d052ac2f79e229"
        },
        {
          "name": "https://github.com/gohugoio/hugo/releases/tag/v0.163.1",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/gohugoio/hugo/releases/tag/v0.163.1"
        }
      ],
      "source": {
        "advisory": "GHSA-c3wq-j5vh-68rc",
        "discovery": "UNKNOWN"
      },
      "title": "Hugo symlink confinement bypass in os.ReadFile"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-58403",
    "datePublished": "2026-07-06T19:25:45.971Z",
    "dateReserved": "2026-06-30T18:19:58.379Z",
    "dateUpdated": "2026-07-06T20:51:27.624Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

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.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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.