What’s Vulnerable › Vulnerabilities

CVE-2019-25634: Base64 Decoder 1.1.2 Local Buffer Overflow SEH Egghunter

• Severity: high (CVSS 7.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-03-24 · updated 2026-06-17
• Weakness: CWE-787

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.

Affected products

• 4Mhz Base64 Decoder: 1.1.2

References

• http://4mhz.de/b64dec.html
• http://4mhz.de/download.php?file=b64dec-1-1-2.zip
• https://www.exploit-db.com/exploits/46625
• https://www.vulncheck.com/advisories/base64-decoder-local-buffer-overflow-seh-egghunter

Get alerted when CVE-2019-25634 or the next vulnerability affects your stack