#VU52858 Heap-based buffer overflow in Exim - CVE-2020-28013

Vulnerability identifier: #VU52858

Vulnerability risk: Low

CVSSv4.0: 5.9 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2020-28013

CWE-ID: CWE-122

Exploitation vector: Local

Exploit availability: No

Vulnerable software:
Exim
Server applications / Mail servers

Vendor: Exim

Description

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to a boundary error in parse_fix_phrase() function. A local user can trigger heap-based buffer overflow and execute arbitrary code with elevated privileges.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Exim: 4.00 - 4.94.1

---

External links
https://seclists.org/oss-sec/2021/q2/91

---

Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.