A heap-based buffer overflow in the awarrensmtp component of Sophos XG Firewall v17.5 MR11 and older potentially allows an attacker to run…

published 2020-06-18 6 y ago modified 2026-06-17 4 mo ago also EUVD-2020-3856

cvss: 9.8; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 1.4%; EPSS 1.4% chance of exploitation in 30 days, percentile 73%
public exploits: 0; none known

A heap-based buffer overflow in the awarrensmtp component of Sophos XG Firewall v17.5 MR11 and older potentially allows an attacker to run arbitrary code remotely.

Patch / fix

fixed in 1

sophos sfos 17.5

Exploit prediction

1.44% chance of exploitation in the next 30 days, higher than 73% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
NVD	3.1	9.8	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD	2.0	7.5	AV:N/AC:L/Au:N/C:P/I:P/A:P

Classification

Weakness

CWE-787 Out-of-bounds Write

References

community.sophos.com /b/security-blog/posts/advisory-potential-rce-through-heap-overflow-in-awarrensmtp-cve-2020-11503
vendor-advisory

Sources

CVE List CVE-2020-11503
NVD CVE-2020-11503

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary