Exim libspf2 Integer Underflow Remote Code Execution Vulnerability
33Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 7.5epss 52%
exploitation probability
52%top 1% of all CVEs
observed exploitation
nono source reports it
In short
Exim's SPF macro parser has an integer underflow flaw that allows remote attackers to execute arbitrary code without authentication. Attackers can send specially crafted SPF records that exploit improper validation to write malicious data into memory and take control of the mail service.
Technical detail
An integer underflow vulnerability exists in libspf2's SPF macro parsing routine due to insufficient input validation. A network-adjacent attacker can send crafted SPF data to trigger the underflow, leading to out-of-bounds memory writes and arbitrary code execution with service account privileges; no authentication required.
Summary generated and translated by AI from the official description.
Exim libspf2 Integer Underflow Remote Code Execution Vulnerability. This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of Exim libspf2. Authentication is not required to exploit this vulnerability.
The specific flaw exists within the parsing of SPF macros. When parsing SPF macros, the process does not properly validate user-supplied data, which can result in an integer underflow before writing to memory. An attacker can leverage this vulnerability to execute code in the context of the service account.
. Was ZDI-CAN-17578.
CVSS:3.0/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Affected products
Exim · libspf2