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CVE-2019-10735

Status: ModifiedMedium (4.3)—

In Claws Mail 3.14.1, an attacker in possession of S/MIME or PGP encrypted emails can wrap them as sub-parts within a crafted multipart email. The encrypted part(s) can further be hidden using HTML/CSS or ASCII newline characters. This modified multipart email can be re-sent by the attacker to the intended receiver. If the receiver replies to this (benign looking) email, they unknowingly leak the plaintext of the encrypted message part(s) back to the attacker.

CVSS

Exploitation probability (EPSS)

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

Affected technologies (1)

Claws-mail — Mail

CWEs

References

Raw JSON (NVD)

Show
{
  "id": "CVE-2019-10735",
  "cveTags": [],
  "metrics": {
    "cvssMetricV2": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "version": "2.0",
          "baseScore": 4.3,
          "accessVector": "NETWORK",
          "vectorString": "AV:N/AC:M/Au:N/C:N/I:P/A:N",
          "authentication": "NONE",
          "integrityImpact": "PARTIAL",
          "accessComplexity": "MEDIUM",
          "availabilityImpact": "NONE",
          "confidentialityImpact": "NONE"
        },
        "acInsufInfo": false,
        "impactScore": 2.9,
        "baseSeverity": "MEDIUM",
        "obtainAllPrivilege": false,
        "exploitabilityScore": 8.6,
        "obtainUserPrivilege": false,
        "obtainOtherPrivilege": false,
        "userInteractionRequired": true
      }
    ],
    "cvssMetricV30": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.0",
          "baseScore": 4.3,
          "attackVector": "NETWORK",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N",
          "integrityImpact": "LOW",
          "userInteraction": "REQUIRED",
          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 1.4,
        "exploitabilityScore": 2.8
      }
    ]
  },
  "affected": [
    {
      "source": "cve@mitre.org",
      "affectedData": [
        {
          "vendor": "n/a",
          "product": "n/a",
          "versions": [
            {
              "status": "affected",
              "version": "n/a"
            }
          ]
        }
      ]
    }
  ],
  "published": "2019-04-07T15:29:00.340",
  "references": [
    {
      "url": "https://www.thewildbeast.co.uk/claws-mail/bugzilla/show_bug.cgi?id=4159",
      "tags": [
        "Exploit",
        "Issue Tracking",
        "Third Party Advisory"
      ],
      "source": "cve@mitre.org"
    },
    {
      "url": "https://www.thewildbeast.co.uk/claws-mail/bugzilla/show_bug.cgi?id=4159",
      "tags": [
        "Exploit",
        "Issue Tracking",
        "Third Party Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    }
  ],
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "CWE-319"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "In Claws Mail 3.14.1, an attacker in possession of S/MIME or PGP encrypted emails can wrap them as sub-parts within a crafted multipart email. The encrypted part(s) can further be hidden using HTML/CSS or ASCII newline characters. This modified multipart email can be re-sent by the attacker to the intended receiver. If the receiver replies to this (benign looking) email, they unknowingly leak the plaintext of the encrypted message part(s) back to the attacker."
    },
    {
      "lang": "es",
      "value": "En Claws Mail 3.14.1 un atacante que posea correos electrónicos cifrados en S/MIME o PGP puede envolverlos como subpartes de un correo electrónico multiparte manipulado. La(s) parte(s) cifrada(s) se puede(n) ocultar aún más utilizando caracteres de nuevas líneas ASCII o HTML/CSS. Este correo electrónico multiparte manipulado puede ser reenviado por el atacante al destinatario previsto. Si el destinatario responde a este correo (de aspecto benigno), estaría filtrando el texto plano de algunas partes del mensaje cifrado sin querer, devolviéndoselas al atacante."
    }
  ],
  "lastModified": "2026-06-17T02:11:34.610",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:claws-mail:mail:3.14.1:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "CB877174-D91A-4CCA-B274-0D9B6E6BF058"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "cve@mitre.org"
}