Skip to main content

Exim CVE-2016-9963

MEDIUM
Key Management Errors (CWE-320)
2017-02-01 cve@mitre.org
Information Disclosure Debian Canonical Debian Linux Ubuntu Linux Exim
5.9
CVSS 3.0 · NVD
View

Vulnerability Assessment

Weakness
CWE
CWE-320
OWASP Top 10:2025
A04:2025 - Cryptographic Failures
ASVS 5.0
V11 - Cryptography Key management controls
Impact

CVSS score of 5.9 (MEDIUM). Attack characteristics: network attack vector, high complexity, no privileges required, no user interaction not required. EPSS exploitation probability: 1.68%.
Exploit ScenarioDerived

This vulnerability can be exploited remotely over the network. Successful exploitation could compromise the medium-severity affected system.
This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
No patch listed yet 1.7% exploitation probability (EPSS)

Get an e-mail when this CVE is exploited, patched or re-scored. Free account.

Alert me

AnalysisAI

Exim before 4.87.1 might allow remote attackers to obtain the private DKIM signing key via vectors related to log files and bounce messages. Rated medium severity (CVSS 5.9), this vulnerability is remotely exploitable, no authentication required. No vendor patch available.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Sign in to check
Technical ContextAI · show details

This vulnerability is classified under CWE-320. Exim before 4.87.1 might allow remote attackers to obtain the private DKIM signing key via vectors related to log files and bounce messages. Affected products include: Exim, Canonical Ubuntu Linux, Debian Debian Linux. Version information: before 4.87.1.

Know when Exim gets its next vulnerability

  • Watch products and get an email when something new is published
  • Check this CVE against your own stack and servers
  • Exploit and PoC references, threat intelligence from 22 sources
Continue with Google Continue with GitHub

No credit card · 7-day full trial

Severity by source

NVD PRIMARY 5.9 MEDIUM
AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

DescriptionCVE.org

Exim before 4.87.1 might allow remote attackers to obtain the private DKIM signing key via vectors related to log files and bounce messages.

Threat Intelligence Overview

EPSS Score
1.7%
Top 18% exploitable
Data Quality
3 sources
Confidence: Low
NVD CVE.org EPSS

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC No
EPSS 1.7%
Patch available No
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation· derived
None
System Exposure· derived
Open
Automatable· derived
No
Human Impact· derived
Medium

Priority Score

32
Low Medium High Critical
KEV: 0
EPSS: +2
CVSS: +30
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Information Disclosure MEDIUM

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.

Affected Products (CPE)CVE.org

cpe:2.3:a:exim:exim:*:*:*:*:*:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:12.04:*:*:*:lts:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:lts:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:16.10:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*

More in Exim

View all
CVE-2017-16943 CRITICAL POC
9.8 Nov 25

The receive_msg function in receive.c in the SMTP daemon in Exim 4.88 and 4.89 allows remote attackers to execute arbitr
CVE-2017-16944 HIGH POC
7.5 Nov 25

The receive_msg function in receive.c in the SMTP daemon in Exim 4.88 and 4.89 allows remote attackers to cause a denial
CVE-2016-1531 HIGH POC
7.0 Apr 07

Exim before 4.86.2, when installed setuid root, allows local users to gain privileges via the perl_startup argument. Rat
CVE-2025-26794 HIGH
7.5 Feb 21

Exim mail server version 4.98 before 4.98.1 contains a remote SQL injection vulnerability when SQLite hints and ETRN ser
CVE-2019-10149 CRITICAL POC
9.8 Jun 05

A flaw was found in Exim versions 4.87 to 4.91 (inclusive). Rated critical severity (CVSS 9.8), this vulnerability is re
CVE-2012-5671 MEDIUM
6.8 Oct 31

Heap-based buffer overflow in the dkim_exim_query_dns_txt function in dkim.c in Exim 4.70 through 4.80, when DKIM suppor
CVE-2022-37452 CRITICAL POC
9.8 Aug 07

Exim before 4.95 has a heap-based buffer overflow for the alias list in host_name_lookup in host.c when sender_host_name
CVE-2019-16928 CRITICAL POC
9.8 Sep 27

Exim 4.92 through 4.92.2 allows remote code execution, a different vulnerability than CVE-2019-15846. Rated critical sev
CVE-2018-6789 CRITICAL POC
9.8 Feb 08

An issue was discovered in the base64d function in the SMTP listener in Exim before 4.90.1. Rated critical severity (CVS
CVE-2020-8015 HIGH POC
7.8 Apr 02

A UNIX Symbolic Link (Symlink) Following vulnerability in the packaging of exim in openSUSE Factory allows local attacke
CVE-2022-37451 HIGH POC
7.5 Aug 06

Exim before 4.96 has an invalid free in pam_converse in auths/call_pam.c because store_free is not used after store_mall
CVE-2020-12783 HIGH POC
7.5 May 11

Exim through 4.93 has an out-of-bounds read in the SPA authenticator that could result in SPA/NTLM authentication bypass

Same weakness CWE-320 – Key Management Errors

View all
CVE-2015-0936 CRITICAL POC
9.8
CVE-2018-0732 HIGH
7.5
CVE-2015-4166 CRITICAL
9.8
CVE-2018-0124 CRITICAL
9.8
CVE-2019-5672 CRITICAL
9.1
CVE-2015-8542 HIGH
8.8
CVE-2025-2220 MEDIUM POC
4.8
CVE-2026-56254 HIGH
8.3

Same technique Information Disclosure

View all
CVE-2019-2725 CRITICAL POC
9.8
CVE-2021-34523 CRITICAL POC
9.0
CVE-2013-2251 CRITICAL POC
9.8
CVE-2017-5638 CRITICAL POC
9.8
CVE-2025-24813 CRITICAL POC
9.8
CVE-2025-68613 HIGH POC
8.8
CVE-2015-1701 HIGH POC
7.8
CVE-2017-0147 HIGH POC
7.5

References

Advisories & patches
ADVISORY http://www.exim.org/static/doc/CVE-2016-9963.txt ADVISORY https://bugs.exim.org/show_bug.cgi?id=1996 REF http://www.debian.org/security/2016/dsa-3747 REF http://www.securityfocus.com/bid/94947 REF http://www.securitytracker.com/id/1037484 REF http://www.ubuntu.com/usn/USN-3164-1

Search Externally

GitHub PoC Exploit-DB PacketStorm Snyk Rapid7 Nuclei Templates Trickest PoC
Back

This site uses cookies essential for authentication and security. No tracking or analytics cookies are used. Privacy Policy