CVE-2019-25634

HIGH

Base64 Decoder 1.1.2 Local Buffer Overflow SEH Egghunter

Title source: cna
STIX 2.1

Exploitation Summary

EIP tracks 1 public exploit for CVE-2019-25634. PoCs published by Paolo Perego.

AI-analyzed exploit summary This exploit demonstrates a local buffer overflow (SEH) in Base64 Decoder 1.1.2, leveraging an egghunter and reverse shell payload to achieve remote code execution. The payload is crafted to bypass bad characters and trigger the vulnerability via a maliciously formatted file.

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.

Exploits (1)

exploitdb WORKING POC
by Paolo Perego · pythonlocalwindows
https://www.exploit-db.com/exploits/46625

This exploit demonstrates a local buffer overflow (SEH) in Base64 Decoder 1.1.2, leveraging an egghunter and reverse shell payload to achieve remote code execution. The payload is crafted to bypass bad characters and trigger the vulnerability via a maliciously formatted file.

Classification
Working Poc 95%
Attack Type
Rce
Complexity
Moderate
Reliability
Reliable
Target: Base64 Decoder 1.1.2
No auth needed
Prerequisites: Victim must open the maliciously crafted file with the vulnerable software
devstral-2 · analyzed Mar 24, 2026 Full analysis →

References (4)

Core 4
Core References
Exploit exploit
ExploitDB-46625
https://www.exploit-db.com/exploits/46625
Product product
Official Product Homepage
http://4mhz.de/b64dec.html
Product product
Product Reference
http://4mhz.de/download.php?file=b64dec-1-1-2.zip
Third Party Advisory third-party-advisory
VulnCheck Advisory: Base64 Decoder 1.1.2 Local Buffer Overflow SEH Egghunter
https://www.vulncheck.com/advisories/base64-decoder-local-buffer-overflow-seh-egghunter

Scores

CVSS v3 8.4
EPSS 0.0026
EPSS Percentile 17.5%
Attack Vector LOCAL
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CISA SSVC

Vulnrichment
Exploitation poc
Automatable no
Technical Impact total

Details

CWE
CWE-787
Status published
Products (2)
4Mhz/Base64 Decoder 1.1.2
4mhz/base64_decoder 1.1.2
Published Mar 24, 2026
Tracked Since Mar 24, 2026