NVD / CVE Program· CNA sonicwall

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…

Noroxi assessment

Priority: This week (action score 65/100)

CISA has confirmed exploitation in the wild (Nov 3, 2021); it is known to be used in ransomware campaigns. Remediation deadline for US federal agencies: Nov 17, 2021.
Probability of exploitation in the next 30 days: 51.6% (FIRST EPSS); higher than 98.9% of all records.
Anyone who can reach it over the internet can trigger it. Administrator privileges are required. No user action is required. No special conditions are required; it is repeatable.
According to CISA the attack is automatable: targets can be found by mass scanning.
According to the record, no fixed version is available yet.
Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Don’t wait for the next maintenance window. Until a fix is released, restrict access to the affected component and follow the vendor's advisory.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · CISA KEV · FIRST EPSS

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.

MediumCVSS 4.9 · v3.1KEVWeaponized No fix recorded

Path traversal

Published: Apr 20, 2021
Updated: Oct 1, 2026
EPSS: 51.6% · 98th percentile
CWE: CWE-22

Report tools

JSON

Action score

This week

Don’t wait for the next maintenance window.

CVSS: 19 / 40 · 4.9 / 10
CISA KEV: 30 / 30 · Listed
EPSS: 16 / 30 · 51.6%

CISA SSVC decision

Exploitation: active
Automatable: yes
Technical impact: total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: 4.9
CNA · sonicwall: 4.9; agree

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Actively exploited in the wild

CISA added this to its Known Exploited Vulnerabilities catalog on Nov 3, 2021. That signals real attacks, not theory.

Remediation deadline for US federal agencies: Nov 17, 2021.

Known to be used in ransomware campaigns.

Get told when this record changes

In CISA KEV: exploitation in the wild confirmed
Weaponized exploit exists
No fixed version yet

If any of these changes, we'll tell you in the daily email digest.

Is your version affected? Check it

Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

We use this product, ask for help

Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
sonicwall	email security	cpe:2.3:a:sonicwall:email_security
sonicwall	email security appliance 9000 firmware	cpe:2.3:o:sonicwall:email_security_appliance_9000_firmware
sonicwall	email security appliance 9000	cpe:2.3:h:sonicwall:email_security_appliance_9000
sonicwall	email security appliance 3300 firmware	cpe:2.3:o:sonicwall:email_security_appliance_3300_firmware
sonicwall	email security appliance 3300	cpe:2.3:h:sonicwall:email_security_appliance_3300
sonicwall	email security appliance 4300 firmware	cpe:2.3:o:sonicwall:email_security_appliance_4300_firmware
sonicwall	email security appliance 4300	cpe:2.3:h:sonicwall:email_security_appliance_4300
sonicwall	email security appliance 8300 firmware	cpe:2.3:o:sonicwall:email_security_appliance_8300_firmware
sonicwall	email security appliance 8300	cpe:2.3:h:sonicwall:email_security_appliance_8300
sonicwall	email security appliance 5000 firmware	cpe:2.3:o:sonicwall:email_security_appliance_5000_firmware
sonicwall	email security appliance 5000	cpe:2.3:h:sonicwall:email_security_appliance_5000
sonicwall	email security appliance 7000 firmware	cpe:2.3:o:sonicwall:email_security_appliance_7000_firmware

and 8 more

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

sonicwall email securitybefore 10.0.9.6173
sonicwall email security appliance 3300 firmwarebefore 10.0.9.6177
sonicwall email security appliance 4300 firmwarebefore 10.0.9.6177
sonicwall email security appliance 5000 firmwarebefore 10.0.9.6177
sonicwall email security appliance 5050 firmwarebefore 10.0.9.6177
sonicwall email security appliance 7000 firmwarebefore 10.0.9.6177
sonicwall email security appliance 7050 firmwarebefore 10.0.9.6177
sonicwall email security appliance 8300 firmwarebefore 10.0.9.6177
sonicwall email security appliance 9000 firmwarebefore 10.0.9.6177
sonicwall email security virtual appliancebefore 10.0.9.6177
sonicwall hosted email securitybefore 10.0.9.6173

Versions reported by the vendor

Affected version ranges reported by the assigning authority (sonicwall). Independent of NVD's CPE analysis and usually ahead of it.

SonicWall Email Security
- 10.0.9 and earlieraffected

Same product

sonicwall: all records

Other highest-scoring records for the same primary product.

CVE-2021-20021A vulnerability in the SonicWall Email Security version 10.0.9.x allows an attacker to create an administrative account by sending a…KEV
96Now
CVE-2021-20022SonicWall Email Security version 10.0.9.x contains a vulnerability that allows a post-authenticated attacker to upload an arbitrary file to…KEV
63This week
CVE-2026-66150Improper Control of Generation of Code ('Code Injection') Vulnerability in the SonicWall Email Security appliance allows an authenticated…
31Monitor

Published before and after this one in the same product

Later →CVE-2023-0655Feb 13, 2023 · SonicWall Email Security contains a vulnerability that could permit a remote unauthenticated attacker access to an error page that includes…
21Monitor
Later →CVE-2024-22398Mar 14, 2024 · An improper Limitation of a Pathname to a Restricted Directory (Path Traversal) vulnerability in SonicWall Email Security Appliance could…
19Monitor
Later →CVE-2026-3468Mar 31, 2026 · A stored Cross-Site Scripting (XSS) vulnerability has been identified in the SonicWall Email Security appliance due to improper…
19Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

Weaponized

A ready exploit tool or active in-the-wild use is known for this vulnerability. This should be your top priority.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

PublishedApr 20, 2021
CISA KEVNov 3, 2021+196 d
TodayNov 11, 2026+2031 d

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

TR-21-0337 · Apr 21, 2021(SonicWall Güvenlik Zafiyeti)

All national notices →

Technical details

Attack conditions

Anyone who can reach it over the internet can trigger it.
Administrator privileges are required.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality: high · data can be read
Integrity: none
Availability: none

Attack vector: Network
Attack complexity: Low
Privileges required: High
User interaction: None
Scope: Unchanged
Confidentiality impact: High
Integrity impact: None
Availability impact: None

Weakness class (CWE)

CWE-22 · Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N

nvd-primary

Root cause

A user-supplied file name is joined with the allowed directory, but the result is never checked to confirm it is still inside that directory.

The bug in code

The whole CWE-22 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1const file = path.join(ROOT, req.query.name);
2res.sendFile(file);

Fixed

1const file = path.resolve(ROOT, req.query.name);
2if (!file.startsWith(ROOT + path.sep)) {
3  return res.sendStatus(400);
4}
5res.sendFile(file);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Attack patterns (CAPEC)

ATT&CK techniques

—

Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

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

Show all references (1 more)

www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-20023

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records