CVE-2019-25634

HIGH 8.4

Base64 Decoder 1.1.2 Local Buffer Overflow SEH Egghunter

CVSS Score

8.4

EPSS Score

0.0%

EPSS Percentile

2th

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.

CWE	CWE-787
Vendor	4mhz
Product	base64 decoder
Published	Mar 24, 2026
Last Updated	Mar 24, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector

Local

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Affected Versions

4Mhz / Base64 Decoder

1.1.2

References

NVD ↗ CVE.org ↗ EPSS Data ↗

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

Credits

Paolo Perego - [email protected]