Buffer overflow in 4mhz Base64 Decoder
CVE-2019-25634
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.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.4 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.003 (16.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 17th percentile — 16.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000
Affected products
- 4mhz Base64 Decoder — versions 1.1.2
- 4mhz Base64 Decoder — versions 1.1.2
Weakness classification (CWE)
References
- ExploitDB-46625 (Exploit, exploit)
- Official Product Homepage (Product, product, Release Notes)
- Product Reference (Product, product)
- VulnCheck Advisory: Base64 Decoder 1.1.2 Local Buffer Overflow SEH Egghunter (Third Party Advisory, third-party-advisory)
Frequently asked questions
- What is CVE-2019-25634?
- CVE-2019-25634 is a high-severity vulnerability in 4mhz Base64 Decoder, classified under Out-of-bounds Write. CVSS score: 8.4/10. Published 2026-03-24.
- How severe is CVE-2019-25634?
- High severity. CVSS v3 base score is 8.4 out of 10.