CVE-2020-28024

Debian Security Advisory 4912-1

Severity Score

9.8

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

Exim 4 before 4.94.2 allows Buffer Underwrite that may result in unauthenticated remote attackers executing arbitrary commands, because smtp_ungetc was only intended to push back characters, but can actually push back non-character error codes such as EOF.

Exim 4 versiones anteriores a 4.94.2, permite una Subscripción de Búfer que puede resultar en que unos atacantes remotos no autenticados ejecuten comandos arbitrarios, porque la función smtp_ungetc solo tenía la intención de retroceder caracteres, pero actualmente puede retroceder códigos de error que no son caracteres como EOF

USN-4934-1 fixed several vulnerabilities in Exim. This update provides the corresponding update for Ubuntu 14.04 ESM and Ubuntu 16.04 ESM. CVE-2020-28026 only affected Ubuntu 16.04 ESM. It was discovered that Exim contained multiple security issues. An attacker could use these issues to cause a denial of service, execute arbitrary code remotely, obtain sensitive information, or escalate local privileges. Various other issues were also addressed.

*Credits: N/A

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Attack Vector

Network

Attack Complexity

Low

Authentication

None

Confidentiality

Partial

Integrity

Partial

Availability

Partial

* Common Vulnerability Scoring System

SSVC

Decision:-

Exploitation

Automatable

Tech. Impact

* Organization's Worst-case Scenario

Timeline

2020-10-30 CVE Reserved
2021-05-06 CVE Published
2024-08-04 CVE Updated
2025-03-30 EPSS Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-787: Out-of-bounds Write

CAPEC

References (1)

URL	Tag	Source
https://www.exim.org/static/doc/security/CVE-2020-qualys/CVE-2020-28024-UNGET.txt	Third Party Advisory

URL	Date	SRC

URL	Date	SRC

URL	Date	SRC

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
Exim Search vendor "Exim"		Exim Search vendor "Exim" for product "Exim"				>= 4.00 < 4.94.2 Search vendor "Exim" for product "Exim" and version " >= 4.00 < 4.94.2"		-		Affected