{"id":"CVE-2026-104721","title":"Path-traversal vulnerability in QOS.CH Sarl Logback-classic on Java (logback-classic module) allows path-traversal vulnerability","summary":"Path-traversal vulnerability in QOS.CH Sarl Logback-classic on Java (logback-classic module) allows path-traversal vulnerability. More specifically, an \nMDC-based discriminator value flows unsanitized into a nested \nFileAppender path, le…","severity":"medium","cvss":6.3,"cvssVector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/S:P/AU:N/RE:M/U:Green","cwe":["CWE-22"],"vendor":"QOS.CH Sarl","product":"Logback-classic","affected":["Logback-classic >= 0.9.14 <= 1.6.4"],"published":"2026-10-02","updated":"2026-10-02","sourceUpdated":"2026-10-02T14:17:10.167","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-104721","references":[{"url":"https://logback.qos.ch/news.html#1.6.5","label":"vulnerability@ncsc.ch"}],"tags":["nvd","cve.org"],"cvssSource":"cna","ingestedAt":"2026-10-02T14:20:32.572Z","slug":"CVE-2026-104721","body":"## Overview\n\nPath-traversal vulnerability in QOS.CH Sarl Logback-classic on Java (logback-classic module) allows path-traversal vulnerability. More specifically, an \nMDC-based discriminator value flows unsanitized into a nested \nFileAppender path, letting an attacker who influences that MDC value \n(e.g. via an HTTP header)\n create and append log files outside the intended directory. \n\n\nThis issue affects Logback-classic: from 0.9.14 through 1.6.4.  This vulnerability is similar to CVE-2026-19880 but involves other attack techniques.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":35,"depthScoreParts":{"impact":34.7,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}