Denial of service in Exim

1) Use-after-free

EUVDB-ID: #VU69579

Risk: Medium

CVSSv4.0: 6.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2022-3559

CWE-ID: CWE-416 - Use After Free

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to a use-after-free error in the regex handler. A remote attacker can send specially crafted data to the mail server, trigger a use-after-free error and perform a denial of service (DoS) attack.

Successful exploitation of the vulnerability may allow an attacker to compromise vulnerable system.

Mitigation

Cybersecurity Help is currently unaware of any official solution to address this vulnerability.

Vulnerable software versions

Exim: 4.87 - 4.96

CPE2.3

• cpe:2.3:a:exim:exim:4.87:*:*:*:*:*:*:*
• cpe:2.3:a:exim:exim:4.87.1:*:*:*:*:*:*:*
• cpe:2.3:a:exim:exim:4.88:*:*:*:*:*:*:*

External links

https://git.exim.org/exim.git/commit/4e9ed49f8f12eb331b29bd5b6dc3693c520fddc2
https://bugs.exim.org/show_bug.cgi?id=2915
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/WFHLZVHNNO2GWYP5EA4TZQZ5O4GVPARR/
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/TMQ6OCKPNPBPSD37YR4FOWV2R54M2UEP/
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/EIH4W5R7SHTUEQFWWKB4TUO5YFZX64KV/

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

How the attacker can exploit this vulnerability?

The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

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