GCVE Workshop - 22 September 2026 (14:00-18:00), Luxembourg Before The Vulnopticon Conference - Registration

CVE-2026-1225 (GCVE-0-2026-1225)

Vulnerability from cvelistv5 – Published: 2026-01-22 09:24 – Updated: 2026-01-22 14:14
VLAI
Title
Malicious logback.xml configuration file allows instantiation of arbitrary classes
Summary
ACE vulnerability in configuration file processing by QOS.CH logback-core up to and including version 1.5.24 in Java applications, allows an attacker to instantiate classes already present on the class path by compromising an existing logback configuration file. The instantiation of a potentially malicious Java class requires that said class is present on the user's class-path. In addition, the attacker must have write access to a configuration file. However, after successful instantiation, the instance is very likely to be discarded with no further ado.
Severity
1.8 (Low)
CVSS:4.0/AV:L/AC:H/AT:P/PR:H/UI:N/VC:L/VI:L/VA:L/SC:L/SI:L/SA:L/S:N/AU:N/RE:M/U:Green
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-01-22 14:14 UTC
CWE
  • CWE-20 - Improper Input Validation
Assigner
References
Impacted products
Vendor Product Version CPE status
QOS.CH Sarl Logback-core Affected: 0.9.20 , ≤ 1.5.24 (maven)
Unaffected: 1.5.25
guessed Create a notification for this product.
Credits
https://www.code-intelligence.com/ Google Fuzz
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-1225",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-01-22T14:14:09.436515Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-01-22T14:14:17.842Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unknown",
          "modules": [
            "logback-core",
            "logback-classic"
          ],
          "platforms": [
            "Java"
          ],
          "product": "Logback-core",
          "vendor": "QOS.CH Sarl",
          "versions": [
            {
              "lessThanOrEqual": "1.5.24",
              "status": "affected",
              "version": "0.9.20",
              "versionType": "maven"
            },
            {
              "status": "unaffected",
              "version": "1.5.25"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "https://www.code-intelligence.com/"
        },
        {
          "lang": "en",
          "type": "finder",
          "value": "Google Fuzz"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "\u003cdiv\u003eACE vulnerability in configuration file processing  by QOS.CH logback-core up to and including version 1.5.24 in Java applications, allows an attacker to instantiate classes already present on the class path by compromising an existing logback configuration file.\u003c/div\u003e\u003cdiv\u003e\u003cbr\u003e\u003c/div\u003e\u003cdiv\u003eThe instantiation of a potentially malicious Java class requires that said class is present on the user\u0027s class-path. In addition, the attacker must  have write access to a \nconfiguration file. However, after successful instantiation, the instance is very likely to be discarded with no further ado.\u003c/div\u003e"
            }
          ],
          "value": "ACE vulnerability in configuration file processing  by QOS.CH logback-core up to and including version 1.5.24 in Java applications, allows an attacker to instantiate classes already present on the class path by compromising an existing logback configuration file.\n\n\n\n\nThe instantiation of a potentially malicious Java class requires that said class is present on the user\u0027s class-path. In addition, the attacker must  have write access to a \nconfiguration file. However, after successful instantiation, the instance is very likely to be discarded with no further ado."
        }
      ],
      "exploits": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "No known exploitation\u003cbr\u003e"
            }
          ],
          "value": "No known exploitation"
        }
      ],
      "impacts": [
        {
          "descriptions": [
            {
              "lang": "en",
              "value": "Arbitrary code execution on previously compromised system"
            }
          ]
        },
        {
          "capecId": "CAPEC-242",
          "descriptions": [
            {
              "lang": "en",
              "value": "CAPEC-242 Code Injection"
            }
          ]
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "Automatable": "NO",
            "Recovery": "NOT_DEFINED",
            "Safety": "NEGLIGIBLE",
            "attackComplexity": "HIGH",
            "attackRequirements": "PRESENT",
            "attackVector": "LOCAL",
            "baseScore": 1.8,
            "baseSeverity": "LOW",
            "exploitMaturity": "NOT_DEFINED",
            "privilegesRequired": "HIGH",
            "providerUrgency": "GREEN",
            "subAvailabilityImpact": "LOW",
            "subConfidentialityImpact": "LOW",
            "subIntegrityImpact": "LOW",
            "userInteraction": "NONE",
            "valueDensity": "NOT_DEFINED",
            "vectorString": "CVSS:4.0/AV:L/AC:H/AT:P/PR:H/UI:N/VC:L/VI:L/VA:L/SC:L/SI:L/SA:L/S:N/AU:N/RE:M/U:Green",
            "version": "4.0",
            "vulnAvailabilityImpact": "LOW",
            "vulnConfidentialityImpact": "LOW",
            "vulnIntegrityImpact": "LOW",
            "vulnerabilityResponseEffort": "MODERATE"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-20",
              "description": "CWE-20 Improper Input Validation",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-01-22T12:10:39.562Z",
        "orgId": "455daabc-a392-441d-aa46-37d35189897c",
        "shortName": "NCSC.ch"
      },
      "references": [
        {
          "url": "https://logback.qos.ch/news.html#1.5.25"
        }
      ],
      "solutions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "Update to logback version 1.5.25 or later. \u003cbr\u003e"
            }
          ],
          "value": "Update to logback version 1.5.25 or later."
        }
      ],
      "source": {
        "discovery": "UNKNOWN"
      },
      "title": "Malicious logback.xml configuration file allows instantiation of arbitrary classes",
      "x_generator": {
        "engine": "Vulnogram 0.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "455daabc-a392-441d-aa46-37d35189897c",
    "assignerShortName": "NCSC.ch",
    "cveId": "CVE-2026-1225",
    "datePublished": "2026-01-22T09:24:14.634Z",
    "dateReserved": "2026-01-20T12:29:25.357Z",
    "dateUpdated": "2026-01-22T14:14:17.842Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-1225",
      "date": "2026-09-20",
      "epss": "0.00165",
      "percentile": "0.06152"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "defaultStatus": "unknown",
                "modules": [
                  "logback-core",
                  "logback-classic"
                ],
                "platforms": [
                  "Java"
                ],
                "product": "Logback-core",
                "vendor": "QOS.CH Sarl",
                "versions": [
                  {
                    "lessThanOrEqual": "1.5.24",
                    "status": "affected",
                    "version": "0.9.20",
                    "versionType": "maven"
                  },
                  {
                    "status": "unaffected",
                    "version": "1.5.25"
                  }
                ]
              }
            ],
            "source": "vulnerability@ncsc.ch"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "ACE vulnerability in configuration file processing  by QOS.CH logback-core up to and including version 1.5.24 in Java applications, allows an attacker to instantiate classes already present on the class path by compromising an existing logback configuration file.\n\n\n\n\nThe instantiation of a potentially malicious Java class requires that said class is present on the user\u0027s class-path. In addition, the attacker must  have write access to a \nconfiguration file. However, after successful instantiation, the instance is very likely to be discarded with no further ado."
          },
          {
            "lang": "es",
            "value": "Vulnerabilidad ACE en el procesamiento de archivos de configuraci\u00f3n por QOS.CH logback-core hasta la versi\u00f3n 1.5.24 inclusive en aplicaciones Java, permite a un atacante instanciar clases ya presentes en el classpath comprometiendo un archivo de configuraci\u00f3n de logback existente.\n\nLa instanciaci\u00f3n de una clase Java potencialmente maliciosa requiere que dicha clase est\u00e9 presente en el classpath del usuario. Adem\u00e1s, el atacante debe tener acceso de escritura a un archivo de configuraci\u00f3n. Sin embargo, despu\u00e9s de una instanciaci\u00f3n exitosa, es muy probable que la instancia sea descartada sin m\u00e1s pre\u00e1mbulos."
          }
        ],
        "id": "CVE-2026-1225",
        "lastModified": "2026-06-17T10:15:21.373",
        "metrics": {
          "cvssMetricV40": [
            {
              "cvssData": {
                "Automatable": "NO",
                "Recovery": "NOT_DEFINED",
                "Safety": "NEGLIGIBLE",
                "attackComplexity": "HIGH",
                "attackRequirements": "PRESENT",
                "attackVector": "LOCAL",
                "availabilityRequirement": "NOT_DEFINED",
                "baseScore": 1.8,
                "baseSeverity": "LOW",
                "confidentialityRequirement": "NOT_DEFINED",
                "exploitMaturity": "NOT_DEFINED",
                "integrityRequirement": "NOT_DEFINED",
                "modifiedAttackComplexity": "NOT_DEFINED",
                "modifiedAttackRequirements": "NOT_DEFINED",
                "modifiedAttackVector": "NOT_DEFINED",
                "modifiedPrivilegesRequired": "NOT_DEFINED",
                "modifiedSubAvailabilityImpact": "NOT_DEFINED",
                "modifiedSubConfidentialityImpact": "NOT_DEFINED",
                "modifiedSubIntegrityImpact": "NOT_DEFINED",
                "modifiedUserInteraction": "NOT_DEFINED",
                "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
                "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
                "modifiedVulnIntegrityImpact": "NOT_DEFINED",
                "privilegesRequired": "HIGH",
                "providerUrgency": "GREEN",
                "subAvailabilityImpact": "LOW",
                "subConfidentialityImpact": "LOW",
                "subIntegrityImpact": "LOW",
                "userInteraction": "NONE",
                "valueDensity": "NOT_DEFINED",
                "vectorString": "CVSS:4.0/AV:L/AC:H/AT:P/PR:H/UI:N/VC:L/VI:L/VA:L/SC:L/SI:L/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:N/AU:N/R:X/V:X/RE:M/U:Green",
                "version": "4.0",
                "vulnAvailabilityImpact": "LOW",
                "vulnConfidentialityImpact": "LOW",
                "vulnIntegrityImpact": "LOW",
                "vulnerabilityResponseEffort": "MODERATE"
              },
              "source": "vulnerability@ncsc.ch",
              "type": "Secondary"
            }
          ],
          "ssvcV203": [
            {
              "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "ssvcData": {
                "id": "CVE-2026-1225",
                "options": [
                  {
                    "exploitation": "none"
                  },
                  {
                    "automatable": "no"
                  },
                  {
                    "technicalImpact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-01-22T14:14:09.436515Z",
                "version": "2.0.3"
              }
            }
          ]
        },
        "published": "2026-01-22T10:16:07.693",
        "references": [
          {
            "source": "vulnerability@ncsc.ch",
            "url": "https://logback.qos.ch/news.html#1.5.25"
          }
        ],
        "sourceIdentifier": "vulnerability@ncsc.ch",
        "vulnStatus": "Deferred",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-20"
              }
            ],
            "source": "vulnerability@ncsc.ch",
            "type": "Secondary"
          }
        ]
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-07-02T21:42:14+00:00",
      "cve": "CVE-2026-1225",
      "id": "CVE-2026-1225",
      "initial_release_date": "2026-01-22T09:24:14.634000+00:00",
      "product_status:known_affected": "66",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "ch.qos.logback/logback-core: Malicious logback.xml configuration file allows instantiation of arbitrary classes",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-1225.json",
      "version": "3"
    },
    "vulnrichment": {
      "containers": {
        "adp": [
          {
            "metrics": [
              {
                "other": {
                  "content": {
                    "id": "CVE-2026-1225",
                    "options": [
                      {
                        "Exploitation": "none"
                      },
                      {
                        "Automatable": "no"
                      },
                      {
                        "Technical Impact": "partial"
                      }
                    ],
                    "role": "CISA Coordinator",
                    "timestamp": "2026-01-22T14:14:09.436515Z",
                    "version": "2.0.3"
                  },
                  "type": "ssvc"
                }
              }
            ],
            "providerMetadata": {
              "dateUpdated": "2026-01-22T14:14:14.793Z",
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP"
            },
            "title": "CISA ADP Vulnrichment"
          }
        ],
        "cna": {
          "affected": [
            {
              "defaultStatus": "unknown",
              "modules": [
                "logback-core",
                "logback-classic"
              ],
              "platforms": [
                "Java"
              ],
              "product": "Logback-core",
              "vendor": "QOS.CH Sarl",
              "versions": [
                {
                  "lessThanOrEqual": "1.5.24",
                  "status": "affected",
                  "version": "0.9.20",
                  "versionType": "maven"
                },
                {
                  "status": "unaffected",
                  "version": "1.5.25"
                }
              ]
            }
          ],
          "credits": [
            {
              "lang": "en",
              "type": "finder",
              "value": "https://www.code-intelligence.com/"
            },
            {
              "lang": "en",
              "type": "finder",
              "value": "Google Fuzz"
            }
          ],
          "descriptions": [
            {
              "lang": "en",
              "supportingMedia": [
                {
                  "base64": false,
                  "type": "text/html",
                  "value": "\u003cdiv\u003eACE vulnerability in configuration file processing  by QOS.CH logback-core up to and including version 1.5.24 in Java applications, allows an attacker to instantiate classes already present on the class path by compromising an existing logback configuration file.\u003c/div\u003e\u003cdiv\u003e\u003cbr\u003e\u003c/div\u003e\u003cdiv\u003eThe instantiation of a potentially malicious Java class requires that said class is present on the user\u0027s class-path. In addition, the attacker must  have write access to a \nconfiguration file. However, after successful instantiation, the instance is very likely to be discarded with no further ado.\u003c/div\u003e"
                }
              ],
              "value": "ACE vulnerability in configuration file processing  by QOS.CH logback-core up to and including version 1.5.24 in Java applications, allows an attacker to instantiate classes already present on the class path by compromising an existing logback configuration file.\n\n\n\n\nThe instantiation of a potentially malicious Java class requires that said class is present on the user\u0027s class-path. In addition, the attacker must  have write access to a \nconfiguration file. However, after successful instantiation, the instance is very likely to be discarded with no further ado."
            }
          ],
          "exploits": [
            {
              "lang": "en",
              "supportingMedia": [
                {
                  "base64": false,
                  "type": "text/html",
                  "value": "No known exploitation\u003cbr\u003e"
                }
              ],
              "value": "No known exploitation"
            }
          ],
          "impacts": [
            {
              "descriptions": [
                {
                  "lang": "en",
                  "value": "Arbitrary code execution on previously compromised system"
                }
              ]
            },
            {
              "capecId": "CAPEC-242",
              "descriptions": [
                {
                  "lang": "en",
                  "value": "CAPEC-242 Code Injection"
                }
              ]
            }
          ],
          "metrics": [
            {
              "cvssV4_0": {
                "Automatable": "NO",
                "Recovery": "NOT_DEFINED",
                "Safety": "NEGLIGIBLE",
                "attackComplexity": "HIGH",
                "attackRequirements": "PRESENT",
                "attackVector": "LOCAL",
                "baseScore": 1.8,
                "baseSeverity": "LOW",
                "exploitMaturity": "NOT_DEFINED",
                "privilegesRequired": "HIGH",
                "providerUrgency": "GREEN",
                "subAvailabilityImpact": "LOW",
                "subConfidentialityImpact": "LOW",
                "subIntegrityImpact": "LOW",
                "userInteraction": "NONE",
                "valueDensity": "NOT_DEFINED",
                "vectorString": "CVSS:4.0/AV:L/AC:H/AT:P/PR:H/UI:N/VC:L/VI:L/VA:L/SC:L/SI:L/SA:L/S:N/AU:N/RE:M/U:Green",
                "version": "4.0",
                "vulnAvailabilityImpact": "LOW",
                "vulnConfidentialityImpact": "LOW",
                "vulnIntegrityImpact": "LOW",
                "vulnerabilityResponseEffort": "MODERATE"
              },
              "format": "CVSS",
              "scenarios": [
                {
                  "lang": "en",
                  "value": "GENERAL"
                }
              ]
            }
          ],
          "problemTypes": [
            {
              "descriptions": [
                {
                  "cweId": "CWE-20",
                  "description": "CWE-20 Improper Input Validation",
                  "lang": "en",
                  "type": "CWE"
                }
              ]
            }
          ],
          "providerMetadata": {
            "dateUpdated": "2026-01-22T12:10:39.562Z",
            "orgId": "455daabc-a392-441d-aa46-37d35189897c",
            "shortName": "NCSC.ch"
          },
          "references": [
            {
              "url": "https://logback.qos.ch/news.html#1.5.25"
            }
          ],
          "solutions": [
            {
              "lang": "en",
              "supportingMedia": [
                {
                  "base64": false,
                  "type": "text/html",
                  "value": "Update to logback version 1.5.25 or later. \u003cbr\u003e"
                }
              ],
              "value": "Update to logback version 1.5.25 or later."
            }
          ],
          "source": {
            "discovery": "UNKNOWN"
          },
          "title": "Malicious logback.xml configuration file allows instantiation of arbitrary classes",
          "x_generator": {
            "engine": "Vulnogram 0.2.0"
          }
        }
      },
      "cveMetadata": {
        "assignerOrgId": "455daabc-a392-441d-aa46-37d35189897c",
        "assignerShortName": "NCSC.ch",
        "cveId": "CVE-2026-1225",
        "datePublished": "2026-01-22T09:24:14.634Z",
        "dateReserved": "2026-01-20T12:29:25.357Z",
        "dateUpdated": "2026-01-22T14:14:17.842Z",
        "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.


Detection rules are retrieved from Rulezet.


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.