Vulnerability-Lookup

GHSA-48X9-G485-9VGW

Vulnerability from github – Published: 2026-10-30 12:31 – Updated: 2026-10-30 12:31

Details

OPNsense core 26.1.6 through 26.7.7 contains an authentication bypass vulnerability in the captive portal roaming feature that lets unauthenticated attackers hijack authorized client sessions by spoofing unauthenticated MAC-to-IP observations. Attackers on the same Layer-2 segment can send forged gratuitous ARP replies binding their IP to a victim's MAC, gaining portal access with traffic attributed to the victim.

Severity

5.4 (Medium)


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

5.3 (Medium)


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

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JSON

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{
  "affected": [],
  "aliases": [
    "CVE-2026-119425"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-290"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-10-30T12:16:39Z",
    "severity": "MODERATE"
  },
  "details": "OPNsense core 26.1.6 through 26.7.7 contains an authentication bypass vulnerability in the captive portal roaming feature that lets unauthenticated attackers hijack authorized client sessions by spoofing unauthenticated MAC-to-IP observations. Attackers on the same Layer-2 segment can send forged gratuitous ARP replies binding their IP to a victim\u0027s MAC, gaining portal access with traffic attributed to the victim.",
  "id": "GHSA-48x9-g485-9vgw",
  "modified": "2026-10-30T12:31:19Z",
  "published": "2026-10-30T12:31:19Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/opnsense/core/security/advisories/GHSA-864r-q4j5-5mjq"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-119425"
    },
    {
      "type": "WEB",
      "url": "https://github.com/opnsense/core/commit/32dc2a3e52eefef5251077f315a0f3243eedb834"
    },
    {
      "type": "WEB",
      "url": "https://github.com/opnsense/core/commit/f46836d0c3d14e26d79214009bfbfa9a1eecab55"
    },
    {
      "type": "WEB",
      "url": "https://abraxaslabs.tech/research/opnsense-captive-lastseen-roam"
    },
    {
      "type": "WEB",
      "url": "https://github.com/opnsense/core"
    },
    {
      "type": "WEB",
      "url": "https://github.com/opnsense/core/blob/26.7.7/src/opnsense/scripts/captiveportal/cp-background-process.py#L78"
    },
    {
      "type": "WEB",
      "url": "https://www.vulncheck.com/advisories/opnsense-26.1.6-through-26.7.7-captive-portal-session-takeover-via-forged-arp"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/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",
      "type": "CVSS_V4"
    }
  ]
}

CVE-2026-119425 (GCVE-0-2026-119425)

Vulnerability from cvelistv5 – Published: 2026-10-30 11:30 – Updated: 2026-10-30 15:55

Title

OPNsense 26.1.6 through 26.7.7 Captive Portal Session Takeover via Forged ARP

Summary

Severity

5.3 (Medium)


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

5.4 (Medium)


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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-10-30 15:20 UTC

CWE

CWE-290 - Authentication Bypass by Spoofing

Assigner

VulnCheck CNA under the mitre root

CNA scorecard B 84/100 over 7156 records in the last 180 days details

References

7 references

URL	Tags
https://github.com/opnsense/core/security/advisor…	vendor-advisory
https://github.com/opnsense/core/commit/f46836d0c…	patch
https://github.com/opnsense/core/commit/32dc2a3e5…	patch
https://github.com/opnsense/core/blob/26.7.7/src/…	technical-description
https://abraxaslabs.tech/research/opnsense-captiv…	third-party-advisory
https://github.com/opnsense/core	product
https://www.vulncheck.com/advisories/opnsense-26.…	third-party-advisory

Impacted products

1 product

Vendor	Product	Version
opnsense	core	Affected: 26.1.6 , ≤ 26.7.7 (semver) cpe:2.3:a:opnsense:opnsense::::::::

Date Public

2026-08-26 00:00

Credits

lujiefsi Abraxas Labs

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-119425",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-10-30T15:20:58.656589Z",
                "version": "2.0.3"
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            }
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        "providerMetadata": {
          "dateUpdated": "2026-10-30T15:55:05.938Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "packageURL": "pkg:github/opnsense/core",
          "product": "core",
          "repo": "https://github.com/opnsense/core",
          "vendor": "opnsense",
          "versions": [
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              "lessThanOrEqual": "26.7.7",
              "status": "affected",
              "version": "26.1.6",
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            }
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      "cpeApplicability": [
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          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:a:opnsense:opnsense:*:*:*:*:*:*:*:*",
                  "versionEndIncluding": "26.7.7",
                  "versionStartIncluding": "26.1.6",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
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      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "lujiefsi"
        },
        {
          "lang": "en",
          "type": "reporter",
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      "datePublic": "2026-08-26T00:00:00.000Z",
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          "lang": "en",
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        }
      ],
      "metrics": [
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            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "attackVector": "ADJACENT",
            "baseScore": 5.3,
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            "privilegesRequired": "NONE",
            "subAvailabilityImpact": "NONE",
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            "userInteraction": "NONE",
            "vectorString": "CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N",
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            "vulnAvailabilityImpact": "NONE",
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        },
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    "datePublished": "2026-10-30T11:30:55.121Z",
    "dateReserved": "2026-10-30T02:41:13.938Z",
    "dateUpdated": "2026-10-30T15:55:05.938Z",
    "state": "PUBLISHED"
  },
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  "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.

Vulnerability timeline

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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.
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