CVE-2020-11503

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2020-06-18 · updated 2026-06-17
Weakness: CWE-787

Description

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.

Affected products

Sophos Firewall: before 17.5; 17.5, 17.5-maintenance_release1, 17.5-maintenance_release10, 17.5-maintenance_release11, 17.5-maintenance_release2, 17.5-maintenance_release3 (+6) — fixed in 17.5

How to fix

Upgrade to a fixed version: Sophos Firewall 17.5. Check the vendor advisory for mitigations.

References

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

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