CVE-2021-20034Public exploitNetwork attack vector

Unauthenticated file deletion via traversal bypass

Published Sep 27, 2021 · Updated Aug 3, 2024

Path traversal in SonicWall SMA 100 Series firmware allows remote attackers to delete arbitrary files through an unauthenticated request. The handleWAFRedirect CGI endpoint accepts a parent-directory path in its hdl parameter and removes the referenced file outside the intended directory. Deleting persist.db and rebooting resets the appliance to factory defaults, enabling administrative access with default credentials.

CVSS severity9.1
Critical
EPSS probability81.01%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Path traversal in SonicWall SMA 100 Series firmware allows remote attackers to delete arbitrary files through an unauthenticated request. The handleWAFRedirect CGI endpoint accepts a parent-directory path in its hdl parameter and removes the referenced file outside the intended directory. Deleting persist.db and rebooting resets the appliance to factory defaults, enabling administrative access with default credentials.

The record

CVE
CVE-2021-20034
Published
Sep 27, 2021
Updated
Aug 3, 2024
Vendor
SonicWall
Product
Secure Mobile Access (SMA) 100 Series
Classifications
CWE-22, CWE-284, T1485
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 27, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=10.2.0.7-34sv and earlier
  2. Affected versionversion=10.2.1.0-17sv and earlier
  3. Affected versionversion=9.0.0.10-28sv and earlier

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

SonicWall · Secure Mobile Access (SMA) 100 Seriesversion=10.2.0.7-34sv and earlier; version=10.2.1.0-17sv and earlier; version=9.0.0.10-28sv and earlier

Published CVSS scores

6.4NVDAV:N/AC:L/Au:N/C:N/I:P/A:P
9.1NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
CWE-284Improper Access Control
T1485Data Destruction

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo