IRONSMITHINTEL
CRITICALCVSS9.8
|
Actively Exploited
|CISA KEV|CVE-2020-15069|Auth: none — unauthenticated|Reboot: required|Manual only

Sophos XG Firewall Buffer Overflow Vulnerability

Sophos XG Firewall contains a buffer overflow vulnerability that allows for remote code execution via the "HTTP/S bookmark" feature.

Published Jun 29, 2020 · Updated May 16, 2026
Why patchRisk explained in plain English
Worst-case scenarioIf unpatched

A remote attacker, without authentication, can achieve full data confidentiality loss, arbitrary modification of data, complete denial of service or system unavailability. Federal agencies are required to remediate by 2025-02-27 under CISA BOD 22-01.

How the attack worksNo clicks needed

This is a Classic Buffer Overflow (CWE-120) vulnerability in Sophos XG Firewall. Exploitation requires remote network access, low attack complexity, no authentication required, and no user interaction required.

📧

Phishing link

🖼

Malicious file

🔓

Server compromised

Am I affected?Quick check

Probably yes if any of these apply:

IT Security
Running xg firewall firmware: 17.0 ≤ v < 17.5, 17.5
Real-world incidentsWhat we've seen

CISA added this CVE to the Known Exploited Vulnerabilities catalog on 2025-02-06 based on evidence of active exploitation in the wild. Federal agencies required to remediate by 2025-02-27.

How to patch

Manual remediation steps

Apply the Vendor Patch

This vulnerability is in the CISA Known Exploited Vulnerabilities catalog — apply the vendor's security update as soon as possible.

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

References

    1
    Vendor advisory: https://community.sophos.com/b/security-blog/posts/advisory-buffer-overflow-vulnerability-in-user-portal
    1
    NVD entry: https://nvd.nist.gov/vuln/detail/CVE-2020-15069
    1
    CISA KEV: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-15069
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