{"id":"CVE-2026-70368","title":"Stunnel: stack-based out-of-bounds read/write in stunnel s_vlog via oversized log message","summary":"A stack-based out-of-bounds read vulnerability exists in the \"s_vlog\" function of stunnel, when handling oversized log messages via \"vsnprintf\". A remote attacker with network access to a stunnel service can send protocol inputs that tri…","severity":"medium","cvss":6.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L","cvssSource":"cna","cwe":["CWE-125"],"vendor":"Mobi-Com Polska Sp. z o.o.","product":"stunnel","affected":["stunnel >= 5.68 < 5.80","stunnel (all versions)","stunnel","stunnel","stunnel (all versions)","stunnel (all versions)"],"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"partial","timestamp":"2026-08-04T14:21:17.494804Z"},"published":"2026-08-04","updated":"2026-11-05","sourceUpdated":"2026-11-05T22:51:55.471Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-70368","references":[{"url":"https://access.redhat.com/security/cve/CVE-2026-70368"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2462029","label":"RHBZ#2462029"}],"tags":["cve.org"],"epss":0.00353,"epssPercentile":0.2915,"ingestedAt":"2026-11-05T23:41:31.938Z","slug":"CVE-2026-70368","body":"## Overview\n\nA stack-based out-of-bounds read vulnerability exists in the \"s_vlog\" function of stunnel, when handling oversized log messages via \"vsnprintf\". A remote attacker with network access to a stunnel service can send protocol inputs that trigger a log message longer than 1024 bytes, leading to an out-of-bounds stack read and a potential crash. In certain corner cases, the same vulnerability could be used to replace a series of trailing \"\\n\" characters with \"\\0\".\n\n## Affected\n\n- `stunnel >= 5.68 < 5.80`\n- `stunnel (all versions)`\n- `stunnel`\n- `stunnel`\n- `stunnel (all versions)`\n- `stunnel (all versions)`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n### Workarounds\n\nTo mitigate this issue, avoid exposing stunnel services to untrusted clients. Restrict access to these services to trusted networks only.","depth":"sunlit","depthScore":36,"depthScoreParts":{"impact":35.8,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}