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FKIE_CVE-2026-61911

Vulnerability from fkie_nvd - Published: 2026-09-09 20:18 - Updated: 2026-09-10 19:17
Severity
4.3 (Medium) - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Summary
An issue was discovered in Cyrus IMAP before 3.12.4. There is a Sieve mailbox existence oracle. An authenticated user could install a Sieve script that probed whether another user's private mailbox existed, or read the value of shared mailbox annotations, by observing which fileinto branch fired during LMTP delivery.
References
cve@mitre.orghttps://cyrusimap.org
cve@mitre.orghttps://www.cyrusimap.org/3.12/imap/download/release-notes/3.10/x/3.10.4.html
cve@mitre.orghttps://www.cyrusimap.org/3.12/imap/download/release-notes/3.12/x/3.12.4.html
cve@mitre.orghttps://www.cyrusimap.org/3.12/imap/download/release-notes/3.8/x/3.8.8.html
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Cyrus IMAP",
          "vendor": "cyrusimap",
          "versions": [
            {
              "lessThan": "3.8.8",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThan": "3.10.4",
              "status": "affected",
              "version": "3.9.0",
              "versionType": "semver"
            },
            {
              "lessThan": "3.12.4",
              "status": "affected",
              "version": "3.11.0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "source": "cve@mitre.org"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "An issue was discovered in Cyrus IMAP before 3.12.4. There is a Sieve mailbox existence oracle. An authenticated user could install a Sieve script that probed whether another user\u0027s private mailbox existed, or read the value of shared mailbox annotations, by observing which fileinto branch fired during LMTP delivery."
    }
  ],
  "id": "CVE-2026-61911",
  "lastModified": "2026-09-10T19:17:31.507",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 4.3,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "LOW",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 1.4,
        "source": "cve@mitre.org",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-61911",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-09-10T18:59:21.694757Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-09-09T20:18:36.800",
  "references": [
    {
      "source": "cve@mitre.org",
      "url": "https://cyrusimap.org"
    },
    {
      "source": "cve@mitre.org",
      "url": "https://www.cyrusimap.org/3.12/imap/download/release-notes/3.10/x/3.10.4.html"
    },
    {
      "source": "cve@mitre.org",
      "url": "https://www.cyrusimap.org/3.12/imap/download/release-notes/3.12/x/3.12.4.html"
    },
    {
      "source": "cve@mitre.org",
      "url": "https://www.cyrusimap.org/3.12/imap/download/release-notes/3.8/x/3.8.8.html"
    }
  ],
  "sourceIdentifier": "cve@mitre.org",
  "vulnStatus": "Undergoing Analysis",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-497"
        }
      ],
      "source": "cve@mitre.org",
      "type": "Secondary"
    }
  ]
}



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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.


Detection rules are retrieved from Rulezet.