Use After Free Vulnerability in Exim Mail Server by Exim
CVE-2020-28018

9.8CRITICAL

Key Information:

Vendor

Exim

Status
Exim
Vendor
CVE Published:
6 May 2021

Badges

👾 Exploit Exists🟡 Public PoC🟣 EPSS 62%

What is CVE-2020-28018?

Exim Mail Server versions prior to 4.94.2 are susceptible to a Use After Free vulnerability within the smtp_reset function. This vulnerability tends to occur in specific scenarios typical for builds utilizing OpenSSL, potentially leading to unexpected behavior or security implications. System administrators are encouraged to evaluate their Exim installations to determine if they are running affected versions and apply appropriate patches to mitigate risks.

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2020-28018
Created by dorkerdevil

CVE-2020-28018
Created by zr0tt

References

https://www.exim.org/static/doc/security/CVE-2020-qualys/...
x_refsource_MISC
http://www.openwall.com/lists/oss-security/2021/05/11/5
mailing-listx_refsource_MLIST
http://www.openwall.com/lists/oss-security/2021/05/11/6
mailing-listx_refsource_MLIST

EPSS Score

62% chance of being exploited in the next 30 days.

CVSS V3.1

Score:
9.8
Severity:
CRITICAL
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

.