FKIE_CVE-2026-46431

Vulnerability from fkie_nvd - Published: 2026-05-26 17:16 - Updated: 2026-07-24 11:10
Severity
4.3 (Medium) - CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N
Summary
Algernon is a small self-contained pure-Go web server. Prior to 1.17.7, the SSE event server's Access-Control-Allow-Origin response header was hardcoded to the wildcard * regardless of the caller's Origin. Because EventSource does not preflight and does not send cookies, the wildcard is sufficient to let any third-party page the developer visits open a cross-origin EventSource to the SSE port and read the live filename stream from JavaScript. This vulnerability is fixed in 1.17.7.
References
security-advisories@github.comhttps://github.com/xyproto/algernon/security/advisories/GHSA-hw27-4v2q-5qff
134c704f-9b21-4f2e-91b3-4a467353bcc0https://github.com/xyproto/algernon/security/advisories/GHSA-hw27-4v2q-5qff
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "algernon",
          "vendor": "xyproto",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 1.17.7"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Algernon is a small self-contained pure-Go web server. Prior to 1.17.7, the SSE event server\u0027s Access-Control-Allow-Origin response header was hardcoded to the wildcard * regardless of the caller\u0027s Origin. Because EventSource does not preflight and does not send cookies, the wildcard is sufficient to let any third-party page the developer visits open a cross-origin EventSource to the SSE port and read the live filename stream from JavaScript. This vulnerability is fixed in 1.17.7."
    },
    {
      "lang": "es",
      "value": "Algernon es un peque\u00f1o servidor web autocontenido pure-Go. Antes de la 1.17.7, el encabezado de respuesta Access-Control-Allow-Origin del servidor de eventos SSE estaba codificado de forma r\u00edgida al comod\u00edn * independientemente del Origin del llamador. Debido a que EventSource no realiza una solicitud de pre-vuelo y no env\u00eda cookies, el comod\u00edn es suficiente para permitir que cualquier p\u00e1gina de terceros que el desarrollador visite abra un EventSource de origen cruzado al puerto SSE y lea el flujo de nombres de archivo en vivo desde JavaScript. Esta vulnerabilidad est\u00e1 corregida en la 1.17.7."
    }
  ],
  "id": "CVE-2026-46431",
  "lastModified": "2026-07-24T11:10:00.170",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 4.3,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "LOW",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "REQUIRED",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 1.4,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-46431",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-05-26T17:38:47.158630Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-05-26T17:16:51.100",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/xyproto/algernon/security/advisories/GHSA-hw27-4v2q-5qff"
    },
    {
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "url": "https://github.com/xyproto/algernon/security/advisories/GHSA-hw27-4v2q-5qff"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-942"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    }
  ]
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.

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

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

Sightings and recorded dates, grouped by day · UTC

JSON

Loading timeline…




    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.