What is CVE-2023-1671?

CVE-2023-1671 is a critical-severity vulnerability in Sophos Web Appliance, classified under Command Injection. CVSS score: 9.8/10. Published 2023-04-04.

How severe is CVE-2023-1671?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Is CVE-2023-1671 known to be exploited?

Yes. CVE-2023-1671 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2023-11-16), indicating it is being actively exploited. 15 public proof-of-concept repositories are indexed.

RCE in Sophos Web Appliance

CVE-2023-1671

A pre-auth command injection vulnerability in the warn-proceed handler of Sophos Web Appliance older than version 4.3.10.4 allows execution of arbitrary code.

Vulnerability class: Command Injection (OS Command Injection)

Published 2023-04-04 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 1.000 (100.0th percentile), scored 2026-09-24.

Very high probability of exploitation in the next 30 days — among the top 0.1% most-likely-to-be-exploited CVEs. 100th percentile — 100.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

The 30-day trend appears once there are two daily scores.

Affected products

Sophos Web Appliance — versions unspecified
Sophos Web Appliance

Weakness classification (CWE)

CWE-77 — Command Injection

CISA KEV (Known Exploited Vulnerabilities)

This CVE is on the CISA KEV catalog, added on 2023-11-16. CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.

BOD 22-01 due date: 2023-12-07.

Required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

Public proof-of-concept exploits

References

www.sophos.com/en-us/security-advisories/sophos-sa-20230404-swa-rce (Vendor Advisory)
packetstormsecurity.com/files/172016/Sophos-Web-Appliance-4.3.10.4-Command-Inje… (Exploit, VDB Entry, Third Party Advisory)
134c704f-9b21-4f2e-91b3-4a467353bcc0 (US Government Resource)

Frequently asked questions

What is CVE-2023-1671?: CVE-2023-1671 is a critical-severity vulnerability in Sophos Web Appliance, classified under Command Injection. CVSS score: 9.8/10. Published 2023-04-04.
How severe is CVE-2023-1671?: Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2023-1671 known to be exploited?: Yes. CVE-2023-1671 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2023-11-16), indicating it is being actively exploited. 15 public proof-of-concept repositories are indexed.