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CVE-2023-42117

Exim Improper Neutralization of Special Elements Remote Code Execution Vulnerability

8.1 HighFix available

Exim 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.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
High
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
High
Integrity
High
Availability
High

Exploit likelihood

6.79%Up 6.7 points since May 3, 2024
90%50%10%1%

What each source reports

CVE List Score used 8.1

Exim Improper Neutralization of Special Elements Remote Code Execution Vulnerability

Exim 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.

Record
CVE-2023-42117
CVSS 3.0
8.1 HighCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness
CWE-138
Updated
2026-11-02
EUVDEUVD-2023-46576 8.1

Exim 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.

Record
EUVD-2023-46576
CVSS 3.0
8.1 HighCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Updated
2026-11-02
GitHub AdvisoriesGHSA-qf54-2qx8-3vcv 8.1

Exim Improper Neutralization of Special Elements Remote Code Execution Vulnerability. This...

Exim 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.

Record
GHSA-qf54-2qx8-3vcv
CVSS 3.0
8.1 HighCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness
CWE-138
Updated
2026-11-02
NVD 9.8

Exim 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.

Record
CVE-2023-42117
CVSS 3.1
9.8 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS 3.0
8.1 HighCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness
CWE-138
Updated
2026-11-02
OSVALPINE-CVE-2023-42117 9.8

Exim 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.

Record
ALPINE-CVE-2023-42117
CVSS 3.1
9.8 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Updated
2026-11-03
OSV 8.1

Exim Improper Neutralization of Special Elements Remote Code Execution Vulnerability

Exim 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.

Record
CVE-2023-42117
CVSS 3.0
8.1 HighCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness
CWE-138
Updated
2026-11-02
Show 11 moreShow less
OSVDEBIAN-CVE-2023-42117 9.8

Exim 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.

Record
DEBIAN-CVE-2023-42117
CVSS 3.1
9.8 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Updated
2026-11-02
OSVUBUNTU-CVE-2023-42117 9.8

Exim 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.

Record
UBUNTU-CVE-2023-42117
CVSS 3.1
9.8 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS 3.0
8.1 HighCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Updated
2026-11-02
OSVCLSA-2023-1700160152 No score

Fix CVE(s): CVE-2023-42117

  • SECURITY UPDATE: Remote code execution because of improper neutralization of special elements
    • debian/patches/CVE-2023-42117.patch: fix string_is_ip_address()
    • CVE-2023-42117
Record
CLSA-2023-1700160152
Updated
2026-11-02
OSVCLSA-2023-1700160963 No score

Fix CVE(s): CVE-2023-42117, CVE-2023-42119

  • SECURITY UPDATE: Remote code execution because of improper neutralization of special elements
    • debian/patches/CVE-2023-42117.patch: fix string_is_ip_address()
    • CVE-2023-42117
  • SECURITY UPDATE: dnsdb out-of-bounds read information disclosure
    • debian/patches/CVE-2023-42119.patch: harden dnsdb against crafted DNS responses
    • CVE-2023-42119
Record
CLSA-2023-1700160963
Updated
2026-11-02
OSVCLSA-2023-1701285323 No score

exim: Fix of CVE-2023-42117

  • CVE-2023-42117: fix string_is_ip_address()
Record
CLSA-2023-1701285323
Updated
2026-11-02
OSVCLSA-2023-1701285908 No score

exim: Fix of CVE-2023-42117

  • CVE-2023-42117: fix string_is_ip_address()
Record
CLSA-2023-1701285908
Updated
2026-11-02
OSVopenSUSE-SU-2023:0303-1 No score

Security update for exim

This update for exim fixes the following issues:

  • CVE-2023-42117: Fixes Improper Neutralization of Special Elements Remote Code Execution Vulnerability (boo#1215787)
  • CVE-2023-42119: Fixes dnsdb Out-Of-Bounds Read Information Disclosure Vulnerability (boo#1215789)
Record
openSUSE-SU-2023:0303-1
Updated
2026-11-02
OSVopenSUSE-SU-2023:0304-1 No score

Security update for exim

This update for exim fixes the following issues:

  • CVE-2023-42117: Fixes Improper Neutralization of Special Elements Remote Code Execution Vulnerability (boo#1215787)
  • CVE-2023-42119: Fixes dnsdb Out-Of-Bounds Read Information Disclosure Vulnerability (boo#1215789)
Record
openSUSE-SU-2023:0304-1
Updated
2026-11-02
OSVopenSUSE-SU-2024:0007-1 No score

Security update for exim

This update for exim fixes the following issues:

exim was updated to 4.97.1 (boo#1218387, CVE-2023-51766):

  • Fixes for the smtp protocol smuggling (CVE-2023-51766)

exim was updated to exim 4.96:

  • Move from using the pcre library to pcre2.
  • Constification work in the filters module required a major version bump for the local-scan API. Specifically, the 'headers_charset' global which is visible via the API is now const and may therefore not be modified by local-scan code.
  • Bug 2819: speed up command-line messages being read in. Previously a time check was being done for every character; replace that with one per buffer.
  • Bug 2815: Fix ALPN sent by server under OpenSSL. Previously the string sent was prefixed with a length byte.
  • Change the SMTP feature name for pipelining connect to be compliant with RFC 5321. Previously Dovecot (at least) would log errors during submission.
  • Fix macro-definition during '-be' expansion testing. The move to write-protected store for macros had not accounted for these runtime additions; fix by removing this protection for '-be' mode.
  • Convert all uses of select() to poll().
  • Fix use of $sender_host_name in daemon process. When used in certain main-section options or in a connect ACL, the value from the first ever connection was never replaced for subsequent connections.
  • Bug 2838: Fix for i32lp64 hard-align platforms
  • Bug 2845: Fix handling of tls_require_ciphers for OpenSSL when a value with underbars is given.
  • Bug 1895: TLS: Deprecate RFC 5114 Diffie-Hellman parameters.
  • Debugging initiated by an ACL control now continues through into routing and transport processes.
  • The 'expand' debug selector now gives more detail, specifically on the result of expansion operators and items.
  • Bug 2751: Fix include_directory in redirect routers. Previously a bad comparison between the option value and the name of the file to be included was done, and a mismatch was wrongly identified.
  • Support for Berkeley DB versions 1 and 2 is withdrawn.
  • When built with NDBM for hints DB's check for nonexistence of a name supplied as the db file-pair basename.
  • Remove the 'allow_insecure_tainted_data' main config option and the 'taint' log_selector.
  • Fix static address-list lookups to properly return the matched item. Previously only the domain part was returned.
  • The ${run} expansion item now expands its command string elements after splitting. Previously it was before; the new ordering makes handling zero-length arguments simpler.
  • Taint-check exec arguments for transport-initiated external processes. Previously, tainted values could be used. This affects 'pipe', 'lmtp' and 'queryprogram' transport, transport-filter, and ETRN commands. The ${run} expansion is also affected: in 'preexpand' mode no part of the command line may be tainted, in default mode the executable name may not be tainted.
  • Fix CHUNKING on a continued-transport. Previously the usabilility of the facility was not passed across execs, and only the first message passed over a connection could use BDAT; any further ones using DATA.
  • Support the PIPECONNECT facility in the smtp transport when the helo_data uses $sending_ip_address and an interface is specified.
  • OpenSSL: fix transport-required OCSP stapling verification under session resumption.
  • TLS resumption: the key for session lookup in the client now includes more info that a server could potentially use in configuring a TLS session, avoiding oferring mismatching sessions to such a server.
  • Fix string_copyn() for limit greater than actual string length.
  • Bug 2886: GnuTLS: Do not free the cached creds on transport connection close; it may be needed for a subsequent connection.
  • Fix CHUNKING for a second message on a connection when the first was rejected.
  • Fix…
Record
openSUSE-SU-2024:0007-1
Updated
2026-11-02
OSVopenSUSE-SU-2024:13333-1 No score

exim-4.96.2-1.1 on GA media

These are all security issues fixed in the exim-4.96.2-1.1 package on the GA media of openSUSE Tumbleweed.

Record
openSUSE-SU-2024:13333-1
Updated
2026-11-02
OSVUSN-6455-1 No score

exim4 vulnerabilities

It was discovered that Exim incorrectly handled validation of user-supplied data, which could lead to memory corruption. A remote attacker could possibly use this issue to execute arbitrary code. (CVE-2023-42117)

It was discovered that Exim incorrectly handled validation of user-supplied data, which could lead to an out-of-bounds read. An attacker could possibly use this issue to expose sensitive information. (CVE-2023-42119)

Record
USN-6455-1
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
exim
Alpine:v3.17
before 4.96.2-r0
4.96.2-r0
exim
Alpine:v3.18
before 4.96.2-r0
4.96.2-r0
exim
Alpine:v3.19
before 4.96.2-r0
4.96.2-r0
exim
Alpine:v3.20
before 4.96.2-r0
4.96.2-r0
exim
Alpine:v3.21
before 4.96.2-r0
4.96.2-r0
exim
Alpine:v3.22
before 4.96.2-r0
4.96.2-r0
exim
Alpine:v3.23
before 4.96.2-r0
4.96.2-r0
exim
Alpine:v3.24
before 4.96.2-r0
4.96.2-r0
exim4
TuxCare:Ubuntu:18.04
before 4.90.1-1ubuntu1.10+tuxcare.els4
4.90.1-1ubuntu1.10+tuxcare.els4
exim4-base
TuxCare:Ubuntu:18.04
before 4.90.1-1ubuntu1.10+tuxcare.els4
4.90.1-1ubuntu1.10+tuxcare.els4
Show 38 moreShow less
Affected packages
PackageAffectedFixed
exim4-config
TuxCare:Ubuntu:18.04
before 4.90.1-1ubuntu1.10+tuxcare.els4
4.90.1-1ubuntu1.10+tuxcare.els4
exim4-daemon-heavy
TuxCare:Ubuntu:18.04
before 4.90.1-1ubuntu1.10+tuxcare.els4
4.90.1-1ubuntu1.10+tuxcare.els4
exim4-daemon-light
TuxCare:Ubuntu:18.04
before 4.90.1-1ubuntu1.10+tuxcare.els4
4.90.1-1ubuntu1.10+tuxcare.els4
exim4-dev
TuxCare:Ubuntu:18.04
before 4.90.1-1ubuntu1.10+tuxcare.els4
4.90.1-1ubuntu1.10+tuxcare.els4
eximon4
TuxCare:Ubuntu:18.04
before 4.90.1-1ubuntu1.10+tuxcare.els4
4.90.1-1ubuntu1.10+tuxcare.els4
exim4
TuxCare:Ubuntu:16.04
before 4.86.2-2ubuntu2.6+tuxcare.els5
4.86.2-2ubuntu2.6+tuxcare.els5
exim4-base
TuxCare:Ubuntu:16.04
before 4.86.2-2ubuntu2.6+tuxcare.els5
4.86.2-2ubuntu2.6+tuxcare.els5
exim4-config
TuxCare:Ubuntu:16.04
before 4.86.2-2ubuntu2.6+tuxcare.els5
4.86.2-2ubuntu2.6+tuxcare.els5
exim4-daemon-heavy
TuxCare:Ubuntu:16.04
before 4.86.2-2ubuntu2.6+tuxcare.els5
4.86.2-2ubuntu2.6+tuxcare.els5
exim4-daemon-light
TuxCare:Ubuntu:16.04
before 4.86.2-2ubuntu2.6+tuxcare.els5
4.86.2-2ubuntu2.6+tuxcare.els5
exim4-dev
TuxCare:Ubuntu:16.04
before 4.86.2-2ubuntu2.6+tuxcare.els5
4.86.2-2ubuntu2.6+tuxcare.els5
eximon4
TuxCare:Ubuntu:16.04
before 4.86.2-2ubuntu2.6+tuxcare.els5
4.86.2-2ubuntu2.6+tuxcare.els5
exim
TuxCare:OracleLinux:6
before 4.92.3-3.el6.tuxcare.els6
4.92.3-3.el6.tuxcare.els6
exim-greylist
TuxCare:OracleLinux:6
before 4.92.3-3.el6.tuxcare.els6
4.92.3-3.el6.tuxcare.els6
exim-mon
TuxCare:OracleLinux:6
before 4.92.3-3.el6.tuxcare.els6
4.92.3-3.el6.tuxcare.els6
exim-mysql
TuxCare:OracleLinux:6
before 4.92.3-3.el6.tuxcare.els6
4.92.3-3.el6.tuxcare.els6
exim-pgsql
TuxCare:OracleLinux:6
before 4.92.3-3.el6.tuxcare.els6
4.92.3-3.el6.tuxcare.els6
exim
TuxCare:CentOS:6
before 4.92.3-3.el6.tuxcare.els6
4.92.3-3.el6.tuxcare.els6
exim-greylist
TuxCare:CentOS:6
before 4.92.3-3.el6.tuxcare.els6
4.92.3-3.el6.tuxcare.els6
exim-mon
TuxCare:CentOS:6
before 4.92.3-3.el6.tuxcare.els6
4.92.3-3.el6.tuxcare.els6
exim-mysql
TuxCare:CentOS:6
before 4.92.3-3.el6.tuxcare.els6
4.92.3-3.el6.tuxcare.els6
exim-pgsql
TuxCare:CentOS:6
before 4.92.3-3.el6.tuxcare.els6
4.92.3-3.el6.tuxcare.els6
exim4
Debian:12
before 4.96-15+deb12u3, plus listed versions
4.96-154.96-15+deb12u14.96-15+deb12u2
4.96-15+deb12u3
exim4
Debian:13
before 4.97~RC2-2
4.97~RC2-2
exim4
Debian:14
before 4.97~RC2-2
4.97~RC2-2
exim4
Debian:11
before 4.94.2-7+deb11u4, plus listed versions
4.94.2-74.94.2-7+deb11u14.94.2-7+deb11u24.94.2-7+deb11u3
4.94.2-7+deb11u4
exim4
Ubuntu:Pro:14.04:LTS
before 4.82-3ubuntu2.4+esm7, plus listed versions
4.80-7ubuntu34.80-7ubuntu44.80-9ubuntu14.80-9ubuntu24.82-3ubuntu1
Show 10 moreShow less
4.82-3ubuntu24.82-3ubuntu2.14.82-3ubuntu2.24.82-3ubuntu2.34.82-3ubuntu2.44.82-3ubuntu2.4+esm14.82-3ubuntu2.4+esm24.82-3ubuntu2.4+esm34.82-3ubuntu2.4+esm44.82-3ubuntu2.4+esm6
4.82-3ubuntu2.4+esm7
exim4
Ubuntu:Pro:16.04:LTS
before 4.86.2-2ubuntu2.6+esm5, plus listed versions
4.86-3ubuntu14.86-7ubuntu14.86-7ubuntu24.86-7ubuntu34.86.2-2ubuntu1
Show 10 moreShow less
4.86.2-2ubuntu24.86.2-2ubuntu2.14.86.2-2ubuntu2.24.86.2-2ubuntu2.34.86.2-2ubuntu2.44.86.2-2ubuntu2.54.86.2-2ubuntu2.64.86.2-2ubuntu2.6+esm14.86.2-2ubuntu2.6+esm24.86.2-2ubuntu2.6+esm4
4.86.2-2ubuntu2.6+esm5
exim4
Ubuntu:Pro:18.04:LTS
before 4.90.1-1ubuntu1.10+esm2, plus listed versions
4.89-5ubuntu14.89-9ubuntu14.89-9ubuntu24.89-9ubuntu34.89-9ubuntu4
Show 10 moreShow less
4.90.1-1ubuntu14.90.1-1ubuntu1.14.90.1-1ubuntu1.24.90.1-1ubuntu1.34.90.1-1ubuntu1.44.90.1-1ubuntu1.54.90.1-1ubuntu1.84.90.1-1ubuntu1.94.90.1-1ubuntu1.104.90.1-1ubuntu1.10+esm1
4.90.1-1ubuntu1.10+esm2
exim4
Ubuntu:20.04:LTS
before 4.93-13ubuntu1.9, plus listed versions
4.92.1-1ubuntu34.92.1-1ubuntu44.93~RC2-1ubuntu14.93-9ubuntu14.93-11ubuntu1
Show 7 moreShow less
4.93-12ubuntu14.93-13ubuntu14.93-13ubuntu1.14.93-13ubuntu1.54.93-13ubuntu1.64.93-13ubuntu1.74.93-13ubuntu1.8
4.93-13ubuntu1.9
exim4
Ubuntu:22.04:LTS
before 4.95-4ubuntu2.4, plus listed versions
4.94.2-7ubuntu24.95-2ubuntu24.95-4ubuntu14.95-4ubuntu24.95-4ubuntu2.14.95-4ubuntu2.24.95-4ubuntu2.3
4.95-4ubuntu2.4
exim
SUSE:Package Hub 15 SP5
before 4.94.2-bp155.5.6.1
4.94.2-bp155.5.6.1
exim
openSUSE:Leap 15.5
before 4.94.2-bp155.5.6.1
4.94.2-bp155.5.6.1
exim
SUSE:Package Hub 15 SP4
before 4.94.2-bp154.2.9.1
4.94.2-bp154.2.9.1
exim
openSUSE:Leap 15.4
before 4.94.2-bp154.2.9.1
4.94.2-bp154.2.9.1
exim
SUSE:Package Hub 15 SP5
before 4.97.1-bp155.5.9.1
4.97.1-bp155.5.9.1
exim
openSUSE:Leap 15.5
before 4.97.1-bp155.5.9.1
4.97.1-bp155.5.9.1
exim
openSUSE:Tumbleweed
before 4.96.2-1.1
4.96.2-1.1

History

History
RecordedChangedSources
affected, aliases, referencesOSV
first indexedCVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2023-42117 is a high vulnerability (CVSS 8.1) in Exim, published September 28, 2023. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 6.79%, the 94th percentile. Fixed in exim 4.96.2-r0.

References

Show 24 moreShow less
This page doesn't list everything

Left out here: the rest of 1 source description. The JSON record has them.

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