Exim
Vulnerabilities
67
Known exploited
5
Max CVSS
9.8
Top EPSS
0.99961
Severity breakdown
Critical
19
High
32
Medium
11
Low
5
Affected version ranges
4.00–4.924.00–4.94.24.85–4.924.87–4.914.88–4.94.24.88–4.99.44.90–4.94.24.92–4.92.24.95–4.974.96–4.98.24.97–4.99.34.98–4.98.1< 4.70< 4.90.1< 4.92.2< 4.93.0.4-3.1< 4.94.1< 4.94.2< 4.95< 4.96< 4.96.1< 4.96.2< 4.97< 4.97.1
Also matched as (raw): exim,libspf2
Top vulnerabilities
CVE-2026-45185Exim before 4.99.3, in certain GnuTLS configurations, has a remotely reachable use-after-free in the BDAT body parsing path. It is triggered when a client sends a TLS close_notify mid-body during a CHUNKING transfer, followed by a final cleartext byte on the same TCP connection. This can lead to heap corruption. An unauthenticated network attacker exploiting this vulnerability could execute arbitrary code.
CVE-2026-40685In Exim before 4.99.2, when JSON lookup is enabled, an out-of-bounds heap write can occur when a JSON operator encounters malformed JSON in an untrusted header, because of an incorrect implementation of \ skipping.
CVE-2025-67896Exim before 4.99.1, with certain non-default rate-limit configurations, allows a remote heap-based buffer overflow because database records are cast directly to internal structures without validation.
CVE-2025-26794Exim 4.98 before 4.98.1, when SQLite hints and ETRN serialization are used, allows remote SQL injection.
CVE-2023-42115Exim AUTH Out-Of-Bounds Write Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of Exim. Authentication is not required to exploit this vulnerability.
The specific flaw exists within the smtp service, which listens on TCP port 25 by default. The issue results from the lack of proper validation of user-supplied data, which can result in a write past the end of a buffer. An attacker can leverage this vulnerability to execute code in the context of the service account.
. Was ZDI-CAN-17434.
CVE-2022-37452Exim before 4.95 has a heap-based buffer overflow for the alias list in host_name_lookup in host.c when sender_host_name is set.
CVE-2022-3620A vulnerability was found in Exim and classified as problematic. This issue affects the function dmarc_dns_lookup of the file dmarc.c of the component DMARC Handler. The manipulation leads to use after free. The attack may be initiated remotely. The name of the patch is 12fb3842f81bcbd4a4519d5728f2d7e0e3ca1445. It is recommended to apply a patch to fix this issue. The associated identifier of this vulnerability is VDB-211919.
CVE-2020-28026Exim 4 before 4.94.2 has Improper Neutralization of Line Delimiters, relevant in non-default configurations that enable Delivery Status Notification (DSN). Certain uses of ORCPT= can place a newline into a spool header file, and indirectly allow unauthenticated remote attackers to execute arbitrary commands as root.
CVE-2020-28024Exim 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.
CVE-2020-28022Exim 4 before 4.94.2 has Improper Restriction of Write Operations within the Bounds of a Memory Buffer. This occurs when processing name=value pairs within MAIL FROM and RCPT TO commands.
CVE-2020-28020Exim 4 before 4.92 allows Integer Overflow to Buffer Overflow, in which an unauthenticated remote attacker can execute arbitrary code by leveraging the mishandling of continuation lines during header-length restriction.
CVE-2020-28018Exim 4 before 4.94.2 allows Use After Free in smtp_reset in certain situations that may be common for builds with OpenSSL.
CVE-2020-28017Exim 4 before 4.94.2 allows Integer Overflow to Buffer Overflow in receive_add_recipient via an e-mail message with fifty million recipients. NOTE: remote exploitation may be difficult because of resource consumption.
CVE-2019-16928Exim 4.92 through 4.92.2 allows remote code execution, a different vulnerability than CVE-2019-15846. There is a heap-based buffer overflow in string_vformat in string.c involving a long EHLO command.
CVE-2019-15846Exim before 4.92.2 allows remote attackers to execute arbitrary code as root via a trailing backslash.
CVE-2017-16943The receive_msg function in receive.c in the SMTP daemon in Exim 4.88 and 4.89 allows remote attackers to execute arbitrary code or cause a denial of service (use-after-free) via vectors involving BDAT commands.
CVE-2010-4344Heap-based buffer overflow in the string_vformat function in string.c in Exim before 4.70 allows remote attackers to execute arbitrary code via an SMTP session that includes two MAIL commands in conjunction with a large message containing crafted headers, leading to improper rejection logging.
CVE-2026-40687In Exim before 4.99.2, when the SPA authentication driver is used with an adversarial SPA resource, there can be an out-of-bounds write that crashes the connection instance, or erroneous data processing that divulges data from uninitialized heap memory.
CVE-2019-10149A flaw was found in Exim versions 4.87 to 4.91 (inclusive). Improper validation of recipient address in deliver_message() function in /src/deliver.c may lead to remote command execution.
CVE-2020-28021Exim 4 before 4.94.2 has Improper Neutralization of Line Delimiters. An authenticated remote SMTP client can insert newline characters into a spool file (which indirectly leads to remote code execution as root) via AUTH= in a MAIL FROM command.
CVE-2023-42117Exim Improper Neutralization of Special Elements Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of Exim. Authentication is not required to exploit this vulnerability.
The specific flaw exists within the smtp service, which listens on TCP port 25 by default. The issue results from the lack of proper validation of user-supplied data, which can result in a memory corruption condition. An attacker can leverage this vulnerability to execute code in the context of the current process. Was ZDI-CAN-17554.
CVE-2023-42116Exim SMTP Challenge Stack-based Buffer Overflow Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of Exim. Authentication is not required to exploit this vulnerability.
The specific flaw exists within the handling of NTLM challenge requests. The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a fixed-length stack-based buffer. An attacker can leverage this vulnerability to execute code in the context of the service account.
. Was ZDI-CAN-17515.
CVE-2019-13917Exim 4.85 through 4.92 (fixed in 4.92.1) allows remote code execution as root in some unusual configurations that use the ${sort } expansion for items that can be controlled by an attacker (e.g., $local_part or $domain).
CVE-2018-6789An issue was discovered in the base64d function in the SMTP listener in Exim before 4.90.1. By sending a handcrafted message, a buffer overflow may happen. This can be used to execute code remotely.
CVE-2025-30232A use-after-free in Exim 4.96 through 4.98.1 could allow users (with command-line access) to escalate privileges.