Vulnerability-Lookup

GHSA-42Q8-WW2W-FGMM

Vulnerability from github – Published: 2026-07-10 15:31 – Updated: 2026-07-10 15:31

Details

Capgo before 12.128.2 contains a cross-tenant preview namespace collision vulnerability caused by non-bijective decoding of double underscores to dots in preview hostname parsing. Attackers can register app IDs with underscores that collide with other tenants' dotted app IDs, causing preview misrouting and denial of preview access for victim applications.

Severity

6.4 (Medium)


                  
                    CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:L/A:L

5.3 (Medium)


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

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JSON

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{
  "affected": [],
  "aliases": [
    "CVE-2026-56329"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-436"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-10T15:16:42Z",
    "severity": "MODERATE"
  },
  "details": "Capgo before 12.128.2 contains a cross-tenant preview namespace collision vulnerability caused by non-bijective decoding of double underscores to dots in preview hostname parsing. Attackers can register app IDs with underscores that collide with other tenants\u0027 dotted app IDs, causing preview misrouting and denial of preview access for victim applications.",
  "id": "GHSA-42q8-ww2w-fgmm",
  "modified": "2026-07-10T15:31:40Z",
  "published": "2026-07-10T15:31:40Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/Cap-go/capgo/security/advisories/GHSA-76qq-gg2p-pwwj"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-56329"
    },
    {
      "type": "WEB",
      "url": "https://www.vulncheck.com/advisories/capgo-cross-tenant-preview-namespace-collision-via-non-bijective-underscore-decoding"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:L/A:L",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:L/SC:N/SI:L/SA:L/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",
      "type": "CVSS_V4"
    }
  ]
}

CVE-2026-56329 (GCVE-0-2026-56329)

Vulnerability from cvelistv5 – Published: 2026-07-10 13:57 – Updated: 2026-07-10 15:45

Title

Capgo - Cross-Tenant Preview Namespace Collision via Non-Bijective Underscore Decoding

Summary

Severity

5.3 (Medium)


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

6.4 (Medium)


                        
                          CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:L/A:L

SSVC

Exploitation: poc Automatable: no Technical Impact: partial

CISA Coordinator (v2.0.3)

CWE

CWE-436 - Interpretation Conflict

Assigner

VulnCheck

References

2 references

URL	Tags
https://github.com/Cap-go/capgo/security/advisori…	vendor-advisory
https://www.vulncheck.com/advisories/capgo-cross-…	third-party-advisory

Impacted products

1 product

Vendor	Product	Version
Capgo	Capgo	Affected: 0 , < 12.128.2 (semver) Unaffected: 12.128.2 (semver)

Date Public

2026-05-07 00:00

Credits

Judel777

Show details on NVD website

JSON

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-56329",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-07-10T15:45:10.865078Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-07-10T15:45:22.401Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "references": [
          {
            "tags": [
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            "url": "https://github.com/Cap-go/capgo/security/advisories/GHSA-76qq-gg2p-pwwj"
          }
        ],
        "title": "CISA ADP Vulnrichment"
      }
    ],
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          "product": "Capgo",
          "vendor": "Capgo",
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              "status": "affected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "12.128.2",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "reporter",
          "value": "Judel777"
        }
      ],
      "datePublic": "2026-05-07T00:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
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        }
      ],
      "metrics": [
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          "cvssV4_0": {
            "Automatable": "NOT_DEFINED",
            "Recovery": "NOT_DEFINED",
            "Safety": "NOT_DEFINED",
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            "attackRequirements": "NONE",
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            "baseSeverity": "MEDIUM",
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            "privilegesRequired": "LOW",
            "providerUrgency": "NOT_DEFINED",
            "subAvailabilityImpact": "LOW",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "LOW",
            "userInteraction": "NONE",
            "valueDensity": "NOT_DEFINED",
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            "version": "4.0",
            "vulnAvailabilityImpact": "LOW",
            "vulnConfidentialityImpact": "NONE",
            "vulnIntegrityImpact": "LOW",
            "vulnerabilityResponseEffort": "NOT_DEFINED"
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            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "NONE",
            "integrityImpact": "LOW",
            "privilegesRequired": "LOW",
            "scope": "CHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:L/A:L",
            "version": "3.1"
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      },
      "references": [
        {
          "name": "GitHub Security Advisory (GHSA-76qq-gg2p-pwwj)",
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://github.com/Cap-go/capgo/security/advisories/GHSA-76qq-gg2p-pwwj"
        },
        {
          "name": "VulnCheck Advisory: Capgo - Cross-Tenant Preview Namespace Collision via Non-Bijective Underscore Decoding",
          "tags": [
            "third-party-advisory"
          ],
          "url": "https://www.vulncheck.com/advisories/capgo-cross-tenant-preview-namespace-collision-via-non-bijective-underscore-decoding"
        }
      ],
      "title": "Capgo - Cross-Tenant Preview Namespace Collision via Non-Bijective Underscore Decoding",
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    "datePublished": "2026-07-10T13:57:56.297Z",
    "dateReserved": "2026-06-20T13:06:29.994Z",
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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.

Action not permitted

GHSA-42Q8-WW2W-FGMM

CVE-2026-56329 (GCVE-0-2026-56329)

Tags

Sightings

Nomenclature