What is CVE-2020-15069?

CVE-2020-15069 is a critical-severity vulnerability in Sophos Xg Firewall, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 9.8/10. Published 2020-06-29.

How severe is CVE-2020-15069?

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

Is CVE-2020-15069 known to be exploited?

Yes. CVE-2020-15069 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2025-02-06), indicating it is being actively exploited. 3 public proof-of-concept repositories are indexed.

Buffer overflow in Sophos Xg Firewall

CVE-2020-15069

Sophos XG Firewall 17.x through v17.5 MR12 allows a Buffer Overflow and remote code execution via the HTTP/S Bookmarks feature for clientless access. Hotfix HF062020.1 was published for all firewalls running v17.x.

Vulnerability class: Buffer Overflow

Published 2020-06-29 · 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: 0.107 (95.8th percentile), scored 2026-10-19.

Moderate probability of exploitation in the next 30 days — watch for active exploitation reports. 96th percentile — 95.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.107 · newest: 0.107 · change: 0.000

Affected products

Sophos Xg Firewall
Sophos Xg Firewall Firmware — versions 17.5

Weakness classification (CWE)

CWE-120 — Buffer Copy without Checking Size of Input (Classic Buffer Overflow)

CISA KEV (Known Exploited Vulnerabilities)

This CVE is on the CISA KEV catalog, added on 2025-02-06. 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: 2025-02-27.

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

Public proof-of-concept exploits

References

community.sophos.com/b/security-blog/posts/advisory-buffer-overflow-vulnerabili… (Mitigation, Vendor Advisory)
134c704f-9b21-4f2e-91b3-4a467353bcc0 (US Government Resource)

Frequently asked questions

What is CVE-2020-15069?: CVE-2020-15069 is a critical-severity vulnerability in Sophos Xg Firewall, classified under Buffer Copy without Checking Size of Input (Classic Buffer Overflow). CVSS score: 9.8/10. Published 2020-06-29.
How severe is CVE-2020-15069?: Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2020-15069 known to be exploited?: Yes. CVE-2020-15069 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2025-02-06), indicating it is being actively exploited. 3 public proof-of-concept repositories are indexed.