CVE-2026-35544 (GCVE-0-2026-35544)

Vulnerability from cvelistv5 – Published: 2026-04-03 03:59 – Updated: 2026-04-03 12:50
VLAI
Summary
An issue was discovered in Roundcube Webmail before 1.5.14 and 1.6.14. Insufficient Cascading Style Sheets (CSS) sanitization in HTML e-mail messages may lead to a fixed-position mitigation bypass via the use of !important.
Severity
5.3 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
SSVC
Exploitation: none Automatable: yes Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-04-03 12:50 UTC
CWE
  • CWE-669 - Incorrect Resource Transfer Between Spheres
Assigner
References
Impacted products
Vendor Product Version CPE status
Roundcube Webmail Affected: 0 , < 1.5.14 (semver)
Affected: 1.6.0 , < 1.6.14 (semver)
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-35544",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-04-03T12:50:06.228941Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-04-03T12:50:12.338Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Webmail",
          "vendor": "Roundcube",
          "versions": [
            {
              "lessThan": "1.5.14",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThan": "1.6.14",
              "status": "affected",
              "version": "1.6.0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "An issue was discovered in Roundcube Webmail before 1.5.14 and 1.6.14. Insufficient Cascading Style Sheets (CSS) sanitization in HTML e-mail messages may lead to a fixed-position mitigation bypass via the use of !important."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 5.3,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "NONE",
            "integrityImpact": "LOW",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N",
            "version": "3.1"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-669",
              "description": "CWE-669 Incorrect Resource Transfer Between Spheres",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-04-03T03:59:49.053Z",
        "orgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
        "shortName": "mitre"
      },
      "references": [
        {
          "url": "https://roundcube.net/news/2026/03/18/security-updates-1.7-rc5-1.6.14-1.5.14"
        },
        {
          "url": "https://github.com/roundcube/roundcubemail/releases/tag/1.7-rc5"
        },
        {
          "url": "https://github.com/roundcube/roundcubemail/commit/226811a1c974271dbedca72672923abaff8191c0"
        },
        {
          "url": "https://github.com/roundcube/roundcubemail/releases/tag/1.6.14"
        },
        {
          "url": "https://github.com/roundcube/roundcubemail/commit/099009b9c8e1d3c636fb9a5af72f7c2596018662"
        },
        {
          "url": "https://github.com/roundcube/roundcubemail/releases/tag/1.5.14"
        },
        {
          "url": "https://github.com/roundcube/roundcubemail/commit/57dec0c127b98e0c8e3b9c26c80049b9c4bcaea7"
        }
      ],
      "x_generator": {
        "engine": "CVE-Request-form 0.0.1"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
    "assignerShortName": "mitre",
    "cveId": "CVE-2026-35544",
    "datePublished": "2026-04-03T03:59:49.053Z",
    "dateReserved": "2026-04-03T03:59:48.463Z",
    "dateUpdated": "2026-04-03T12:50:12.338Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-35544",
      "date": "2026-09-23",
      "epss": "0.00366",
      "percentile": "0.30459"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "defaultStatus": "unaffected",
                "product": "Webmail",
                "vendor": "Roundcube",
                "versions": [
                  {
                    "lessThan": "1.5.14",
                    "status": "affected",
                    "version": "0",
                    "versionType": "semver"
                  },
                  {
                    "lessThan": "1.6.14",
                    "status": "affected",
                    "version": "1.6.0",
                    "versionType": "semver"
                  }
                ]
              }
            ],
            "source": "cve@mitre.org"
          }
        ],
        "configurations": [
          {
            "nodes": [
              {
                "cpeMatch": [
                  {
                    "criteria": "cpe:2.3:a:roundcube:webmail:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "8D54F615-2408-47CF-866C-93A7041665CD",
                    "versionEndIncluding": "1.5.13",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:a:roundcube:webmail:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "36D1025D-5F8E-405B-8788-0F8FEE30B3C9",
                    "versionEndIncluding": "1.6.13",
                    "versionStartIncluding": "1.6.0",
                    "vulnerable": true
                  }
                ],
                "negate": false,
                "operator": "OR"
              }
            ]
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "An issue was discovered in Roundcube Webmail before 1.5.14 and 1.6.14. Insufficient Cascading Style Sheets (CSS) sanitization in HTML e-mail messages may lead to a fixed-position mitigation bypass via the use of !important."
          },
          {
            "lang": "es",
            "value": "Se descubri\u00f3 un problema en Roundcube Webmail anterior a las versiones 1.5.14 y 1.6.14. La sanitizaci\u00f3n insuficiente de Hojas de Estilo en Cascada (CSS) en mensajes de correo electr\u00f3nico HTML puede conducir a una omisi\u00f3n de mitigaci\u00f3n de posici\u00f3n fija mediante el uso de !important."
          }
        ],
        "id": "CVE-2026-35544",
        "lastModified": "2026-07-24T21:10:00.143",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "NETWORK",
                "availabilityImpact": "NONE",
                "baseScore": 5.3,
                "baseSeverity": "MEDIUM",
                "confidentialityImpact": "NONE",
                "integrityImpact": "LOW",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N",
                "version": "3.1"
              },
              "exploitabilityScore": 3.9,
              "impactScore": 1.4,
              "source": "cve@mitre.org",
              "type": "Secondary"
            }
          ],
          "ssvcV203": [
            {
              "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "ssvcData": {
                "id": "CVE-2026-35544",
                "options": [
                  {
                    "exploitation": "none"
                  },
                  {
                    "automatable": "yes"
                  },
                  {
                    "technicalImpact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-04-03T12:50:06.228941Z",
                "version": "2.0.3"
              }
            }
          ]
        },
        "published": "2026-04-03T05:16:22.810",
        "references": [
          {
            "source": "cve@mitre.org",
            "tags": [
              "Patch"
            ],
            "url": "https://github.com/roundcube/roundcubemail/commit/099009b9c8e1d3c636fb9a5af72f7c2596018662"
          },
          {
            "source": "cve@mitre.org",
            "tags": [
              "Patch"
            ],
            "url": "https://github.com/roundcube/roundcubemail/commit/226811a1c974271dbedca72672923abaff8191c0"
          },
          {
            "source": "cve@mitre.org",
            "tags": [
              "Patch"
            ],
            "url": "https://github.com/roundcube/roundcubemail/commit/57dec0c127b98e0c8e3b9c26c80049b9c4bcaea7"
          },
          {
            "source": "cve@mitre.org",
            "tags": [
              "Release Notes"
            ],
            "url": "https://github.com/roundcube/roundcubemail/releases/tag/1.5.14"
          },
          {
            "source": "cve@mitre.org",
            "tags": [
              "Release Notes"
            ],
            "url": "https://github.com/roundcube/roundcubemail/releases/tag/1.6.14"
          },
          {
            "source": "cve@mitre.org",
            "tags": [
              "Release Notes"
            ],
            "url": "https://github.com/roundcube/roundcubemail/releases/tag/1.7-rc5"
          },
          {
            "source": "cve@mitre.org",
            "tags": [
              "Vendor Advisory"
            ],
            "url": "https://roundcube.net/news/2026/03/18/security-updates-1.7-rc5-1.6.14-1.5.14"
          }
        ],
        "sourceIdentifier": "cve@mitre.org",
        "vulnStatus": "Analyzed",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-669"
              }
            ],
            "source": "cve@mitre.org",
            "type": "Secondary"
          }
        ]
      }
    },
    "redhat_vex": {
      "current_release_date": "2026-06-28T07:31:52+00:00",
      "cve": "CVE-2026-35544",
      "id": "CVE-2026-35544",
      "initial_release_date": "2026-04-03T03:59:49.053000+00:00",
      "product_status:known_not_affected": "1",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "roundcubemail: Roundcube Webmail: Security mitigation bypass via insufficient CSS sanitization",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-35544.json",
      "version": "3"
    },
    "vulnrichment": {
      "containers": {
        "adp": [
          {
            "metrics": [
              {
                "other": {
                  "content": {
                    "id": "CVE-2026-35544",
                    "options": [
                      {
                        "Exploitation": "none"
                      },
                      {
                        "Automatable": "yes"
                      },
                      {
                        "Technical Impact": "partial"
                      }
                    ],
                    "role": "CISA Coordinator",
                    "timestamp": "2026-04-03T12:50:06.228941Z",
                    "version": "2.0.3"
                  },
                  "type": "ssvc"
                }
              }
            ],
            "providerMetadata": {
              "dateUpdated": "2026-04-03T12:50:09.218Z",
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP"
            },
            "title": "CISA ADP Vulnrichment"
          }
        ],
        "cna": {
          "affected": [
            {
              "defaultStatus": "unaffected",
              "product": "Webmail",
              "vendor": "Roundcube",
              "versions": [
                {
                  "lessThan": "1.5.14",
                  "status": "affected",
                  "version": "0",
                  "versionType": "semver"
                },
                {
                  "lessThan": "1.6.14",
                  "status": "affected",
                  "version": "1.6.0",
                  "versionType": "semver"
                }
              ]
            }
          ],
          "descriptions": [
            {
              "lang": "en",
              "value": "An issue was discovered in Roundcube Webmail before 1.5.14 and 1.6.14. Insufficient Cascading Style Sheets (CSS) sanitization in HTML e-mail messages may lead to a fixed-position mitigation bypass via the use of !important."
            }
          ],
          "metrics": [
            {
              "cvssV3_1": {
                "attackComplexity": "LOW",
                "attackVector": "NETWORK",
                "availabilityImpact": "NONE",
                "baseScore": 5.3,
                "baseSeverity": "MEDIUM",
                "confidentialityImpact": "NONE",
                "integrityImpact": "LOW",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N",
                "version": "3.1"
              },
              "format": "CVSS",
              "scenarios": [
                {
                  "lang": "en",
                  "value": "GENERAL"
                }
              ]
            }
          ],
          "problemTypes": [
            {
              "descriptions": [
                {
                  "cweId": "CWE-669",
                  "description": "CWE-669 Incorrect Resource Transfer Between Spheres",
                  "lang": "en",
                  "type": "CWE"
                }
              ]
            }
          ],
          "providerMetadata": {
            "dateUpdated": "2026-04-03T03:59:49.053Z",
            "orgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
            "shortName": "mitre"
          },
          "references": [
            {
              "url": "https://roundcube.net/news/2026/03/18/security-updates-1.7-rc5-1.6.14-1.5.14"
            },
            {
              "url": "https://github.com/roundcube/roundcubemail/releases/tag/1.7-rc5"
            },
            {
              "url": "https://github.com/roundcube/roundcubemail/commit/226811a1c974271dbedca72672923abaff8191c0"
            },
            {
              "url": "https://github.com/roundcube/roundcubemail/releases/tag/1.6.14"
            },
            {
              "url": "https://github.com/roundcube/roundcubemail/commit/099009b9c8e1d3c636fb9a5af72f7c2596018662"
            },
            {
              "url": "https://github.com/roundcube/roundcubemail/releases/tag/1.5.14"
            },
            {
              "url": "https://github.com/roundcube/roundcubemail/commit/57dec0c127b98e0c8e3b9c26c80049b9c4bcaea7"
            }
          ],
          "x_generator": {
            "engine": "CVE-Request-form 0.0.1"
          }
        }
      },
      "cveMetadata": {
        "assignerOrgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
        "assignerShortName": "mitre",
        "cveId": "CVE-2026-35544",
        "datePublished": "2026-04-03T03:59:49.053Z",
        "dateReserved": "2026-04-03T03:59:48.463Z",
        "dateUpdated": "2026-04-03T12:50:12.338Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



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.