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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 Reserved 2026-03-24 | Published 2026-03-24 | Updated 2026-03-24 | Assigner VulnCheck




HIGH: 8.6CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
HIGH: 8.4CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Problem types

Out-of-bounds Write

Product status

1.1.2
affected

Credits

Paolo Perego - paolo@armoredcode.com finder

References

www.exploit-db.com/exploits/46625 (ExploitDB-46625) exploit

4mhz.de/b64dec.html (Official Product Homepage) product

4mhz.de/download.php?file=b64dec-1-1-2.zip (Product Reference) product

www.vulncheck.com/...der-local-buffer-overflow-seh-egghunter (VulnCheck Advisory: Base64 Decoder 1.1.2 Local Buffer Overflow SEH Egghunter) third-party-advisory

cve.org (CVE-2019-25634)

nvd.nist.gov (CVE-2019-25634)

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