Integer underflow in Exim - CVE-2023-42118

Vulnerability identifier: #VU81255

CSH Severity: Critical

CVSS v4: 9.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2023-42118

CWE-ID: CWE-191

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to integer underflow in libspf2 when parsing SPF macros. A remote attacker can pass specially crafted data to the server, trigger an integer underflow and execute arbitrary code on the target system.

Exim
Fedora
openEuler
libspf2-apidocs
perl-Mail-SPF_XS
libspf2
libspf2-debuginfo
libspf2-debugsource
libspf2-devel
libspf2-progs

Install update from vendor's website.

Exim - addressed in versions 4.96.1, 4.97
libspf2-apidocs - update to 1.2.11-2
perl-Mail-SPF_XS - update to 1.2.11-2
libspf2 - update to 1.2.11-2
libspf2-debuginfo - update to 1.2.11-2
libspf2-debugsource - update to 1.2.11-2
libspf2-devel - update to 1.2.11-2
libspf2-progs - update to 1.2.11-2
libspf2 - addressed in versions 1.2.11-10.20210922git4915c308.el7, 1.2.11-10.20210922git4915c308.el8, 1.2.11-10.20210922git4915c308.el9, 1.2.11-10.20210922git4915c308.fc37, 1.2.11-10.20210922git4915c308.fc38, 1.2.11-10.20210922git4915c308.fc39

• https://www.zerodayinitiative.com/advisories/ZDI-23-1472/
• https://www.exim.org/static/doc/security/CVE-2023-zdi.txt

• Multiple vulnerabilities in Exim
• Fedora EPEL 8 update for libspf2
• Fedora 39 update for libspf2
• Fedora EPEL 9 update for libspf2
• Fedora EPEL 7 update for libspf2
• Fedora 38 update for libspf2
• Fedora 37 update for libspf2
• openEuler 22.03 LTS SP4 update for libspf2
• openEuler 22.03 LTS SP3 update for libspf2
• openEuler 24.03 LTS update for libspf2
• openEuler 24.03 LTS SP1 update for libspf2