{"id":"CVE-2019-25634","url":"https://www.cyber-defence.io/tools/cve/CVE-2019-25634","generatedAt":"2026-10-27T23:38:01.130Z","title":"Base64 Decoder 1.1.2 contains a stack-based buffer overflow vulnerability that allows local attackers to execute arbitrary code by triggering a structured exception handler (SEH) overwrite.","description":"Base64 Decoder 1.1.2 contains a stack-based buffer overflow vulnerability that allows local attackers to execute arbitrary code by triggering a structured exception handler (SEH) overwrite. Attackers can craft a malicious input file that overflows a buffer, overwrites the SEH chain with a POP-POP-RET gadget address, and uses an egghunter payload to locate and execute shellcode for code execution.","published":"2026-03-24T12:16:04.000Z","lastModified":"2026-06-17T02:32:51.000Z","status":"Analyzed","sourceIdentifier":"disclosure@vulncheck.com","cvss":{"version":"4.0","score":8.6,"severity":"HIGH","vector":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M"},"cwe":["CWE-787"],"affected":["4mhz/base64 decoder"],"epss":{"score":0.00266,"percentile":0.18608,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.27%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"http://4mhz.de/b64dec.html","tags":["Product","Release Notes"],"source":"disclosure@vulncheck.com"},{"url":"http://4mhz.de/download.php?file=b64dec-1-1-2.zip","tags":["Product"],"source":"disclosure@vulncheck.com"},{"url":"https://www.exploit-db.com/exploits/46625","tags":["Exploit"],"source":"disclosure@vulncheck.com"},{"url":"https://www.vulncheck.com/advisories/base64-decoder-local-buffer-overflow-seh-egghunter","tags":["Third Party Advisory"],"source":"disclosure@vulncheck.com"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2019-25634","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}