Security Resilience

CVE-2020-15069

Memory Safety in Sophos Xg Firewall Firmware 17.0 – 17.5

CISA KEVActive ExploitationEUVD ExploitedMemory Safety
Published
29 June 2020
Modified
07 November 2025
KEV Added
06 February 2025
Patch / advisory
View advisory
CVSS Score v3.1 9.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.11 96th percentile
Risk Priority 97 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2020-15069 is a critical-severity Classic Buffer Overflow (CWE-120) vulnerability in Sophos Xg Firewall Firmware. Its CVSS base score is 9.8 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique NTDS (T1003.003); ranked in the top 4% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

Sophos XG Firewall versions 17.x through v17.5 MR12 contain a buffer overflow vulnerability tracked as CVE-2020-15069 and CWE-120. The flaw resides in the HTTP/S Bookmarks feature used for clientless access and carries a CVSS 3.1 score of 9.8 reflecting network-accessible, unauthenticated remote code execution with full impact on confidentiality, integrity, and availability.

An unauthenticated attacker can send specially crafted requests to the affected feature over the network, triggering the overflow to execute arbitrary code on the firewall without requiring user interaction or credentials.

Vendor advisories direct administrators to apply the published hotfix HF062020.1 on all v17.x installations, and the issue is documented in Sophos security bulletins.

The vulnerability appears in CISA's catalog of known exploited vulnerabilities, confirming observed in-the-wild attacks against exposed appliances.

EU & UK References

Vulnerability Data

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.

CWE(s)
CWE-120
KEV Date Added
06 February 2025

Related Threats

MITRE ATT&CK Enterprise Techniques

T1003.003 NTDS Credential Access
Adversaries may attempt to access or create a copy of the Active Directory domain database in order to steal credential information, as well as obtain other information about domain members such as devices, users, and access rights.
attack.mitre.org →
T1003.004 LSA Secrets Credential Access
Adversaries with SYSTEM access to a host may attempt to access Local Security Authority (LSA) secrets, which can contain a variety of different credential materials, such as credentials for service accounts.
attack.mitre.org →
T1003.006 DCSync Credential Access
Adversaries may attempt to access credentials and other sensitive information by abusing a Windows Domain Controller's application programming interface (API)(Citation: Microsoft DRSR Dec 2017) (Citation: Microsoft GetNCCChanges) (Citati…
attack.mitre.org →
T1003.008 /etc/passwd and /etc/shadow Credential Access
Adversaries may attempt to dump the contents of <code>/etc/passwd</code> and <code>/etc/shadow</code> to enable offline password cracking.
attack.mitre.org →
T1010 Application Window Discovery Discovery
Adversaries may attempt to get a listing of open application windows.
attack.mitre.org →
T1012 Query Registry Discovery
Adversaries may interact with the Windows Registry to gather information about the system, configuration, and installed software.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2020-12271Same product: Sophos Xg Firewallboth on KEV
CVE-2004-0210Shared CWE-120both on KEV
CVE-2013-0641Shared CWE-120both on KEV
CVE-2023-33010Shared CWE-120both on KEV
CVE-2017-7269Shared CWE-120both on KEV
CVE-2022-37055Shared CWE-120both on KEV
CVE-2013-1331Shared CWE-120both on KEV
CVE-2010-2572Shared CWE-120both on KEV
CVE-2023-41064Shared CWE-120both on KEV
CVE-2023-33009Shared CWE-120both on KEV

Affected Assets

sophos
xg firewall firmware
17.5 · 17.0 — 17.5

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V5.2.1

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

SC-27 Platform-independent Applications
addresses: CWE-120

Platform-independent managed code eliminates the need for unchecked native buffer copies that are the root cause of classic buffer overflows.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

ID.RA-01 partial match
blocks

Vulnerability identification processes such as code review or scanning detect classic buffer overflows before exploitation.

PR.PS-02 partial match
blocks

Routine patching replaces vulnerable code containing unchecked buffer copies with corrected versions.

PR.PS-06 partial match
blocks

Secure development practices directly enforce bounds checking and input validation that prevent classic buffer overflows.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.5.14 Information transfer partial match
removes
A.5.15 Access control partial match
removes
A.5.16 Identity management partial match
removes
A.5.17 Authentication information partial match
removes
A.5.18 Access rights partial match
removes
A.8.10 Information deletion partial match
removes

References