FKIE_CVE-2026-107583

Vulnerability from fkie_nvd - Published: 2026-10-08 12:17 - Updated: 2026-10-08 21:02
Severity
6.5 (Medium) - CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Summary
Inefficient algorithmic complexity in the webmail's message view of the REST API in Progressive Robot hMailServer 6.3.2 through 6.3.5 allows a remote unauthenticated attacker to make the webmail, the administration console and the REST API unavailable by sending a message. The route that renders a received message's HTML replaced each reference to an embedded image in place, with work that grew with the square of the number of references, and wrote the image out for every reference while counting it against its size limit only once. A message whose HTML refers to one small embedded image a very large number of times, opened in the webmail by its recipient, therefore keeps one of the listener's four worker threads busy for minutes and makes it build a document of gigabytes, so that a few such messages leave the HTTP listener unable to answer anybody.
References
cve@gitlab.comhttps://gitlab.com/hmailserver/hmailserver/-/releases/v6.3.6
cve@gitlab.comhttps://gitlab.com/hmailserver/hmailserver/-/work_items/65
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "hMailServer",
          "repo": "https://gitlab.com/hmailserver/hmailserver",
          "vendor": "Progressive Robot Ltd",
          "versions": [
            {
              "lessThan": "6.3.6",
              "status": "affected",
              "version": "6.3.2",
              "versionType": "semver"
            }
          ]
        }
      ],
      "source": "cve@gitlab.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Inefficient algorithmic complexity in the webmail\u0027s message view of the REST API in Progressive Robot hMailServer 6.3.2 through 6.3.5 allows a remote unauthenticated attacker to make the webmail, the administration console and the REST API unavailable by sending a message. The route that renders a received message\u0027s HTML replaced each reference to an embedded image in place, with work that grew with the square of the number of references, and wrote the image out for every reference while counting it against its size limit only once. A message whose HTML refers to one small embedded image a very large number of times, opened in the webmail by its recipient, therefore keeps one of the listener\u0027s four worker threads busy for minutes and makes it build a document of gigabytes, so that a few such messages leave the HTTP listener unable to answer anybody."
    }
  ],
  "id": "CVE-2026-107583",
  "lastModified": "2026-10-08T21:02:43.860",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 6.5,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "REQUIRED",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 3.6,
        "source": "cve@gitlab.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-107583",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-10-08T14:13:59.332199Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-10-08T12:17:16.633",
  "references": [
    {
      "source": "cve@gitlab.com",
      "url": "https://gitlab.com/hmailserver/hmailserver/-/releases/v6.3.6"
    },
    {
      "source": "cve@gitlab.com",
      "url": "https://gitlab.com/hmailserver/hmailserver/-/work_items/65"
    }
  ],
  "sourceIdentifier": "cve@gitlab.com",
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-407"
        }
      ],
      "source": "cve@gitlab.com",
      "type": "Secondary"
    }
  ]
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





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.



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.